Book of Abstracts

VASSCAA-9 - The 9th Vacuum and Surface Science Conference of Asia and Australia

Monday 13 August 2018 - Thursday 16 August 2018 SMC Centre

Book of Abstracts

Contents

Free-Standing Graphene on 3C-SiC Nanostructures 110 ...... 1

Interface Engineering and Emergent Magnetism in Oxide Heterostructures 128 . . . . . 1

Passivation Performance of Tunnel Oxide Passivated Contact Structure by Ozone Oxidation 25 ...... 2

XPSSurfA - An Online Open Access XPS Database 22 ...... 2

Plasma processes that create one-step multi-functionalisable surfaces and nanoparticles: Fundamentals and applications 101 ...... 3

Neutron diffraction of vacuum formed D2O single crystals. 73 ...... 3

Small high density plasma sources for Focussed Ion Beam Applications 80 ...... 4

Lateral graphene/h-BN heterostructures from chemically converted epitaxial graphene on SiC (0001) 55 ...... 4

Lab to Launch 81 ...... 5

The Experimental Realization of Polyphony in Borophene 24 ...... 6

Deposition of Si-incorporated a-C:H films on inner surface of microchannel 37 ...... 6

Neutron transmutation studies of Fe2O3 122 ...... 7

The electronic structure of FeTiO3 121 ...... 7

A Synchrotron Investigation Of The Electronic Structure Of Lanthanide Zirconates 107 . 8

Electronic and vibrational studies of highly doped silicon. 120 ...... 8

Design and Manufacture of a High Resolution Orbital-Trapping Mass-Analyser for Sec- ondary Ion Mass Spectrometry (SIMS) 116 ...... 9

Multispectral Optical Imaging Retrofitted to XPS and ToFSIMS Instruments 113 . . . . . 10

Rapid multivariate analysis of 3D ToF‐SIMS data: graphical processor units (GPUs) for large‐scale principal component analysis 115 ...... 10

Elemental 2D Materials Beyond Graphene 117 ...... 11

Electric Field Tuned Quantum Phase Transition from Topological to Conventional Insulator in Few-Layer Na3Bi 86 ...... 12

iii A Hybrid Hydrogen Storage System Based on Hollow Glass Microspheres 0 ...... 12

Scaling lab research to engage the manufacturing industry: a story of vacuum thin film coatings 90 ...... 13

Surface defect engineering in semiconducting (photo)electrocatalyst 118 ...... 13

X-ray dichroism studies of magnetic anisotropies in thin films 125 ...... 14

Study of hydrogen absorption and desorption properties of oxygen-free Pd/Ti thin film as a non-evaporable getter (NEG) coating by using nuclear reaction analysis (NRA)65 . 15

Adsorption and absorption of hydrogen in Titanium dioxide 102 ...... 16

Neutron Imaging Facility DINGO targetting new fields of research with high resolution upgrade 274 ...... 16

Using light, high energy radiation and theranostic nanomaterials to engineer interactions with biological systems 124 ...... 17

Electronic Structure and Electron Dynamics in Single-Layer Transition Metal Dichalco- genides 91 ...... 17

The Magnetic Properties of Individual Atoms/Molecules on Solid Surfaces 76 ...... 18

Sulfides, Surfaces and Synchrotrons 106 ...... 19

Molecular layer formation on cooled sapphire mirrors in KAGRA Japanese gravitational wave observatory 95 ...... 19

Quantum-Based Pascal and The End of Mercury Manometers 146 ...... 20

Studying Structure at the Liquid/Liquid Interface by Neutron and X-ray Scattering. 224 . 20

Performance of ZnGa2O4 deep ultraviolet photodetectors 142 ...... 21

Growth and fabrication of molybdenum disulfide devices 141 ...... 21

Diamond-Edge Gaskets for the Ultrahigh Vacuum Systems 140 ...... 22

Observation of a resonant-type ground state in graphene intercalated with cerium 93 . . 22

Micro- and nano-tomography with nanoparticles 175 ...... 23

Incorporating nanomaterials into semiconductor technologies 72 ...... 23

What is Brilliant and BRIGHT at the AUstralian Synchrotron 82 ...... 24

Rapid thermal annealing effect on characterizations of CNW by chemical vapor deposition 84 ...... 25

Determining the effect of substrate cleaning on the solution stability of plasma polymer films 17 ...... 25

Mild plasma configuration yielding efficient doping on graphene surface 50 ...... 26

Functional surfaces and devices enabled by two-dimensional materials 257 ...... 26 The role of lattice dynamics in the superconductivity enhancement at FeSe/SrTiO3 interface 63 ...... 27

The electrical properties of carbon nanowalls by the depostion of conductive oxide film20 27

Entropy-Driven Spontaneous Dissociation of Fluoroacetic Acids in Ice 29 ...... 28

Improvement of foreline plasma optical emission spectroscopy for monitoring plasma processes 54 ...... 28

Influence of Metal Assisted Chemical Etching on c-Si Wafer35 ...... 29

Optimization of quantum dots-OLED multistacking EL devices 31 ...... 29

Copper indium gallium selenide (CIGS) solar cell devices on steel substrates coated with thick SiO2-based insulating material 12 ...... 30

Broadband epsilon-near-zero and epsilon-near-pole 1D nanograting metamaterials in near- infrared regime 119 ...... 31

Broadband extraordinary optical transmission in a narrow subwavelength gap of infrared wire-grid-polarizers 52 ...... 32

Iron spin-reorientation transition by dynamic interface alloy formation with Mn 112 . . 32

Reactive sputter deposition of transparent and low refractive-index MgF2 thin films using a double-grid negative-ion retarding electrode 21 ...... 33

Quinary indium gallium zinc aluminum oxide films and thin-film transistors 145 . . . . . 34

High-temperature Corrosion of Chromium(III) Electroplating in N2/0.1%H2S Gas 36 . . . 34

Performance improvement of perovskite solar cells using novel structure design 143 . . 35

Preparation of GeTe chalcogenide solutions for thin film applications 45 ...... 36

Surface hardness of flexible carbon fiber sheets enhanced by deposition of organosilicon oxynitride thin films with an atmospheric pressure plasma jet7 ...... 36

Surface-confined polymerisation: synthetic chemistry without a beaker 53 ...... 37

Molecular nanoarchitectures from on-surface reactions and assembly 18 ...... 38

Environmental XPS characterization of a bioengineered gold nanoparticle/porous silicon interface with calibrated surface conductivity 13 ...... 38

X-ray photoelectron spectroscopy as a tool for control superlattice heterostructures quality and surface bilayer formation 60 ...... 39

On-surface bottom-up synthesis of azine derivatives displaying strong acceptor behavior 69 ...... 39

Electron Accumulation at Semiconducting Surfaces 126 ...... 40

Hierarchical biomimetic porous tantalum fabricated by liquid metal dealloying for biomedical applications 56 ...... 40 Hidden complex magnetic interaction at La0.67Sr0.33O3/SrTiO3:Nb (111) interface 64 . . 41

Low-pressure/environmental electron and photoelectron techniques; a new age for a merged biointerface analysis. 15 ...... 41

Nanoscience as a discipline and its impact on modern society 251 ...... 42

Connected Science for Society: A Key Enabler for Disruptive Innovations 256 ...... 43

Wear performance of Electroless Ni-W-P alloy for coating on the Diamond Powder 92 . . 44

Epitaxial growth of graphene and 2D heterostructures on SiC for nanoelectronic applications 97 ...... 44

Semi-quantitation of VT-XPS spectra of Fe(II) spin-crossover complexes 46 ...... 45

Surface of cavitation-peened Ti-6Al-4V ELI rod for biomedical applications 9 ...... 46

Simple linear relationship between reactive gas flow rate and discharge power at mode transition on reactive sputter deposition of metal oxides 58 ...... 46

Anti-fouling and Slippery Properties of Lubricant-Infused Surfaces 258 ...... 47

Evaluation of Graded Composite Film Morphology 41 ...... 48

Recent highlights in plasma science and applications 254 ...... 48

Antimicrobial nanobiomaterials for scaffolds and medical devices 68 ...... 49

Corrosion behavior of nickel-titanium alloy with TiO2 layer formed via anodization in HNO3 electrolyte 8 ...... 49

Monolithically Integrated Stretchable TFT Array with Liquid Metal Interconnects 11 . . 50

Cu-Assisted Chemical Etching Process for Fabrication of Black Silicon Substrate 34 . . . 50

Composition ratio and structural analysis according to Se injection method in heat treatment process after CIGS single target sputtering 47 ...... 51

Controlling the photocatalytic activity of TiO2 thin films grown by atomic layer deposition 27 ...... 52

Recent Advances in Surface Engineering 177 ...... 52

The Present Status of Siam Photon Source and Recent Development of Soft X-ray Beamline 94 ...... 53

Diamond Surface Functionalization and Doping for Carbon-based Electronics 77 . . . . . 53

Octahedral Engineering and Interfacial Structure of Heteroepitaxial Complex Oxides 33 54

Space Resolved Langmuir Probe Characterization of a DC Magnetron System for Titanium- Aluminum Thin Film Deposition 57 ...... 55

Atmospheric pressure plasmas for the design and tailoring of surfaces and coatings : from fundamental understanding to dedicated surface properties. 103 ...... 55

Oxide based electronics for neuromorphic computing 147 ...... 56 Neutron scattering techniques for understanding restricted dimensionality in magnetism: interfaces, surfaces and more! 87 ...... 56

Atmospheric-pressure microwave plasma system for cleaning and deposition 89 . . . . . 57

Investigation of the Highly Effective Adsorption of Toxic Heavy Metals in Sweat through Multiple Fabric Layers 99 ...... 57

Overview of the Neutron Scattering Capabilities at the OPAL Research Reactor 255 . . . 58

The Preparation of Vertically Standing Graphene Sheets on ITO Glass and Their FieldEmis- sion Properties 85 ...... 58

Manipulating the electronic structure and magnetism of spin-orbit Mott insulator by tailoring superlattices 23 ...... 59

Capturing interface processes at the atomic scale by high-speed surface X-ray diffraction 30 ...... 59

Ferromagnetism of CrO2 under pressure studied using K-edge x-ray magnetic circular dichroism 136 ...... 60

High resolution scanning photoelectron microscopy study of l-cysteine and s-benzyl-l- cysteine on platinum: Adhesion mechanisms and radiation damage 135 ...... 61

The adsorption of glycine on alumina: A search for fundamental mechanisms ofsurface complexation 133 ...... 61

The growth of Mn on Cu(100): A core-level photoemission study 132 ...... 62

The Surface Fermi Surface of Ir{100} 130 ...... 62

The electronic structure of ZrO2/Si(111) 129 ...... 63

The cryogenic and vacuum system for a neutron low-energy bandpass filter spectrometer 108 ...... 63

Field emission arrays characterised by x-ray photoemission electron microscopy 134 . . 64

The electronic structure of S-layer proteins from Lactobacillus brevis 131 ...... 65

Rational Design of Nano-Catalysts for Sustainable Chemicals and Fuels: Insights from The- ory and Simulation 88 ...... 65

Protein-functionalised plasma activated coatings for orthopaedic applications 252 . . . . 66

Towards ARPES at the Australian Synchrotron: 3rd Generation Toroidal Angle Resolving Electron Energy Spectrometer 261 ...... 66

Rapid thermal annealing effect on characterizations of CNW on Si substrate by chemical vapor deposition 83 ...... 67

Photodesorption and Photoelectron Yields from Thin Film Coatings at Cryogenic Temper- ature 51 ...... 67

Dependence of Thermal Conductivity of MPCVD Diamond Thin Films on Oxygen Concen- tration 59 ...... 68 An ex situ near edge X-ray absorption fine structure spectroscopy study of metal phthalocyanine catalysts for CO2 reduction 16 ...... 69

Oxygen Reduction Reaction Activity for Pt/Zr/Pt(111) Model Catalyst Surfaces Prepared by Arc-plasma deposition 6 ...... 69

Hydrogel coating for biomedical devices covalently attached by means of plasma immersion ion implantation 260 ...... 70

Graphene – Cellular Interactions and Implications for Medical Device Technologies 138 . 71

Modelling Driven Discoveries in Molecular Spectroscopy 74 ...... 71

Zero resistance materials and technologies 259 ...... 72

Dark Secrets of the Universe 176 ...... 72

Development of scalable plasma polymerisation processes 96 ...... 73

Key Materials Issues in Co-Sputtered Aluminium-Gallium Oxide Films and Their Applica- tions to Solar-Blind Photodetectors 144 ...... 73

Pyrite oxidation: a comparative study of chemical and air oxidation 32 ...... 74

Fabrication of gasotransmitter releasing amphiphilic copolymeric nanoparticles 98 . . . 74

Neutron studies of iron-based superconductors 137 ...... 75

Characteristics of superimposed dual-frequency inductively coupled plasma source 114 . 76

Confinement-Induced Giant Spin-Orbital-Coupled Magnetic Moment of Co Nanoclusters in TiO2 Films 127 ...... 76

High resolution and radiation-damage free inverse photoelectron spectroscopy 100 . . . 77

Nano- and microfabrication technologies for photovoltaic and supercapacitor device applications 78 ...... 78

Energy-Sensitive Ion- and Cathode-Luminescent Radiation-Beam Monitors Based on Mul- tilayer Thin-Film Design 10 ...... 78

Dye Giant Absorption and Light Confinement Effects in Porous Bragg Microcavities 28 . 79

Highlights of the IUVSTA Thin Film Division 2018 253 ...... 79

Modifying the magnetic reversal mechanism of an exchange biased partially oxides MnxOy/Ni80Fe20 bilayer through oxygen ion implantation 139 ...... 80

Tuning the Electronic Structure of NiO by Li doping for Electrocatalytic Water Oxidation 44 ...... 80

Defects physics in emergent 2D material SnSe with binary black phosphorus lattice 38 . 81

Emerging Challenges in Surface Science 275 ...... 81

Poster Session Themes 207 ...... 82

Poster Session Themes 156 ...... 82 VASSCAA-9 - The 9th Vacuum and Surface Science Conference of Asia … / Book of Abstracts

Speaker Sessions and Seminars / 110

Free-Standing Graphene on 3C-SiC Nanostructures

Mojtaba Amjadipour1 ; Jennifer MacLeod2 ; Josh Lipton-Duffin1 ; Anton TadichNone ; Francesca Iacopi3 ; Nunzio Motta1

1 Queensland University of Technology 2 QUT 3 University of Technology Sydney

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

There is a growing body of literature that recognizes the potential of graphene for use in electronics [1]. However, graphene’s lack of bandgap challenges its remarkable range of applications [2]. The- oretical work suggests that a bandgap might be opened in graphene through quantum confinement, for example in graphene nanoribbons. Thermal decomposition of SiC has proven to be an excellent method to grow transfer-free wafer-scale graphene [3]. Growing graphene on SiC thin films on Si is a cheaper alternative to the growth on bulk SiC. In this research we attempt to manipulate the SiC substrate dimension to grow graphene over nanostructures and use hydrogen intercalation to produce free-standing graphene. SiC mesas have been fabricated by patterning SiC/Si substrates using Focused Ion Beam (FIB) milling [4]. Hydrogen intercalation procedure has been employed at 600 ℃ to fabricate free-standing graphene on the structures [5]. Synchrotron radiation near-edge X-ray absorption fine structure (NEXAFS) with core-level photoelectron spectroscopy (PES), scanning tunnelling microscopy (STM), scanning electron microscopy (SEM), and Raman spectroscopy were used to investigate the process. Our result indicates the possibility of growing free-standing epitaxy graphene over SiC nanostructures. However, more research is needed to better understand the impact of patterning procedure onthe graphene growth and decrease the damage caused by milling process. References [1] M. Kusunoki et al, Journal of the Physical Society of Japan, 84(2015) 121014. [2] K. Novoselov et al, Nature, 438(2005) 197-200. [3] B. Gupta et al, Carbon, 68(2014) 563-572. [4] M. Amjadipour et al, Nanotechnology, 34 (2017) 345602. [5] M. Amjadipour et al, Nanotechnology, 14 (2018) 145601.

Summary:

Speaker Sessions and Seminars / 128

Interface Engineering and Emergent Magnetism in Oxide Het- erostructures

A. Ariando1

1 National University of Singapore

Corresponding Author(s): [email protected]

Complex oxide interfaces have mesmerized the scientific community in the last decade due tothe possibility of creating tunable novel multifunctionalities, which are possible owing to the strong interaction among charge, spin, orbital and structural degrees of freedom. Artificial interfacial mod- ifications, which include defects, formal polarization, structural symmetry breaking and interlayer interaction, have led to novel properties in various complex oxide heterostructures. These emergent phenomena not only serve as a platform for investigating strong electronic correlations in low- dimensional systems, but also provide potentials for exploring next-generation electronic devices

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with high functionality. In particular, emergent magnetism at the oxide interfaces has profound application in future development of spintronic memory. In this talk, I will review our effort in exploring interface magnetism in various different systems. I will then focus on an heterostructure based on CaMnO_3/CaIrO_3 superlattices which is found to possess interface ferrimagnetism by charge transfer, perpendicular magnetic anisotropy up to room temperature, as well as Topological Hall Effect (THE) indicating the presence of magnetic Skyrmion. Emergence of Skyrmions insuch symmetric, antiferromagnet/paramagnet superlattice is the first of its kind, and its stabilization is explained by an “interfacial roughness model”. The abrupt suppression of THE by large current allows measurement of threshold current density of ~10^8 A/m^2 and Skyrmion drift velocities. This system provides a novel route in stabilizing the Skyrmion phase in oxide heterostructure.

Summary:

Poster Session - Main Hall Tuesday / 25

Passivation Performance of Tunnel Oxide Passivated Contact Struc- ture by Ozone Oxidation

Author(s): JongHoon BaekNone

Co-author(s): Hyo Sik Chang

Corresponding Author(s): [email protected], [email protected]

In order to produce a high-efficiency solar cell, it is necessary to increase the passivation effectof the solar cell. Tunnel oxide passivated contact (TOPCon) cell prevents the recombination of carriers by selective carriers collection through tunnelling effect of a very thin silicon oxide layer. In this study, the passivation characteristics of the tunnel oxide layer were observed by growing the ultrathin SiOx layer with ozone oxidation. It was done under the O3 environment at 300 to 500 ℃ with 10.5 to 21 wt% of concentration at 50 torr. The passivation effect of the SiOx layer was compared with the J0 and the implied Voc through quasi-steady-state photoconductance (QSSPC). Moreover, the sub-oxide ratio of the SiOx layer was obtained from X-ray photoelectron spectroscopy (XPS) analysis. In order to evaluate the applicability of TOPCon cell, electrical characteristics were measured with polysilicon on oxide (POLO) junction. iVoc was measured to be 694mV which proved the applicability of TOPCon structure.

Summary:

Speaker Sessions and Seminars / 22

XPSSurfA - An Online Open Access XPS Database

Author(s): Anders Barlow1

Co-author(s): Robert Jones 1 ; Andrew McDonald 1 ; Paul Pigram 1

1 La Trobe University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

X-ray photoelectron spectroscopy (XPS) is a widely used surface analysis technique employed in fundamental research, applied research, service laboratories and industry. Good quality analytical outcomes depend critically on spectral references. Many examples of XPS reference databases exist, including print editions, sets of spectral peak positions drawn from the literature, and digital archives and libraries. We have developed a new digital XPS database comprising survey and region spectra for a range of materials types, collected under a common set of analytical conditions. De- tailed metadata are provided for each material and each spectrum, presented using a schema that incorporates the ISO 16243 and 14976 standards, guidelines developed by IUVSTA technical groups, and extensions developed in this work. Spectra are shared under a Creative Commons International

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(4.0) attribution, non-commercial licence (CC BY-NC) in Kratos (.dset), VAMAS (.vms) andXML (.xml) formats. We will demonstrate the database and its usage, and discuss current case studies incorporating XPSSurfA data.

Summary:

Plenary / 101

Plasma processes that create one-step multi-functionalisable surfaces and nanoparticles: Fundamentals and applications

Marcela Bilek1 ; Elena Kosobrodova1 ; Martin Lewis2 ; Behnam Akhavan1

1 School of Aerospace, Mechanical and Mechatronic Engineering & School of Physics, University of Sydney, NSW 2006, Australia 2 School of Physics, University of Sydney, NSW 2006, Australia

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

Bio-functionalized surfaces are of great interest for a wide range of applications, particularly in biomedical diagnostics and implantable medical devices. We have shown that radicals embedded in polymeric surfaces facilitate simple, one-step surface-functionalisation [1]. The radicals are created by energetic ion bombardment of the surfaces. Covalent immobilisation of functional molecules is achieved by immersion or spotting / painting of the biomolecule-containing solutions onto the activated surfaces. This strategy simplifies covalent functionalisation of surfaces enormously, elim- inating the need for wet-chemistry and the associated solvent disposal and yield problems. This approach has been used to immobilise bioactive peptides, antibodies, enzymes, single stranded DNA, and extra-cellular matrix proteins [2] onto many materials, including polymers, metals and ceramics. This presentation will expound the fundamental science underpinning these new approaches. Pro- cess adaptions that extend the application of these techniques to functionalisation of the internal surfaces of complex, porous materials and structures will be explored. New applications enabling biological studies of the response of individual cells to proteins on a sub-cellular scale [3], and the preparation of multi-functionalisable nanoparticles for theranostics [4] will be elucidated. Finally, we describe recent work which shows that spontaneous covalent immobilisation enabled by surface embedded radicals allows control of the density and orientation of surface-immobilised bioactive peptides [5]. This is achieved by tuning electric fields in the double layer at thesurface during the immobilisation through pH variations and/or the application of external electric fields as delivered by a simple battery. References: [1] Bilek et al, PNAS 108:14405-14410 (2011); [2] Bilek et al, Appl. Surf Sci 310:3-10 (2014); [3] Kosobrodova et al, ACS Appl. Mater. and Interfaces (2018); [4] Santos et al, ACS Appl. Nano Materials (2018); [5] Martin et al, Nat. Comm. 9:357 (2018)

Summary:

Poster Session B / 73

Neutron diffraction of vacuum formed D2O single crystals.

Paolo Imperia1 ; Andrew Studer1 ; Robert AldusNone ; Norman Booth1

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1 ANSTO

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

A number of techniques exist to form water ice single crystals such as following Czochralski , Bridg- man or zone melting methods. These techniques require careful temperature control and thermal contact with some form of refrigerator. The single crystals grown for this study were produced using only the latent heat of vaporisation using standard vacuum equipment and no external refrigeration. The technique is a modification of the method presented by Khunatdinov and Petrenko [1]. The modified technique allowed the preparation of crystals 10mm in diameter and 50mmlongin around 20 minutes. The technique is faster and requires less equipment than the traditional methods mentioned above. Also as the cooling occurs with no physical contact and only on the evaporating surface the possibility of multiple nucleation sites is reduced. The quality of the crystals was measured using neutron diffraction and it was found that the growth direction is inclined to thec-axis and discussions of the implications of this finding are presented. [1] Khusnatdinov, N.N. and Petrenko V.F. , Fast-growth technique for ice single crystals, Journal of Crystal Growth, 163, (1996), 420-425pp

Summary:

Speaker Sessions and Seminars / 80

Small high density plasma sources for Focussed Ion Beam Appli- cations

Rod Boswell1 ; Noel Smith2 ; Paul Tesch2 ; Noel Martin2 ; Christine Charles1

1 ANU 2 Oregon Physics

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected]

Oregon Physics has developed the HyperionTM system of high brightness plasma ion sources which are now being used on Focused Ion Beams and TOF-SIMS around the world. The original research on the plasma source ion beam system was done at the Space Plasma Power and Propulsion Labora- tory at the Australian National University. These plasma sources are ten times brighter than present sources and reduce the time necessary for analysis from days to hours. They are also more reliable and can be focused down to smaller spots. The development of these sources, especially the optimization of the rf antenna design and extraction geometry will be described. Extraction of positive ions is used for reverse engineering on the nano-metre scale and negative ions are used for Time of Flight Secondary Ion Mass Scectroscopy (TOFSIMS). SIMS uses a beam of primary ions (typically O-) focused onto a target. Sputtered secondary ions are measured by mass spectrometer which can detect elements and their isotopes in the low parts per billion (10-9 or ng/g) range. Particles as small as a few 100 nanometres can be analysed. Time of Flight (TOF)SIMS measures the time of arrival of the secondary ions at the detector, which depends on their mass yielding an extremely good high mass resolution. It can detect: cocaine in urine, benzodiazepines (eg. valium) in hair and gunshot residues in fingerprints even after strenuous washing! Additionally, TOF-SIMS can simultaneously detect cocaine in the presence of other drugs (i.e. flurazepam (a benzodiazepine hypnotic) and chlorpromazine (used for psychosis and heroin withdrawal) in urine. It is possible to relate the TOF-SIMS fingerprints to the evidence found at the crime scene, which can be considered as examination of forensic evidence transfer. Elemental composition of anthrax spores using TOF-SIMS has been carried out by Weber et. al. at LLNL. This is of use in assessing the origin of bio-weapons.

Summary:

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Speaker Sessions and Seminars / 55

Lateral graphene/h-BN heterostructures from chemically converted epitaxial graphene on SiC (0001)

Author(s): Jonathan Bradford1 Co-author(s): Josh Lipton-Duffin 1 ; Mahnaz Shafiei 2 ; Jennifer MacLeod 3 ; Nunzio Motta 1

1 Queensland University of Technology 2 Swinburne University of Technology 3 QUT

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

Graphene has attracted a great deal of interest due to its remarkable properties, but as a zero-bandgap semimetal its full potential for next generation electronic devices is yet to be realized. Unlocking its potential for future applications in nanoelectronics will depend critically on the development of novel approaches to introducing a bandgap while preserving carrier mobility. In-plane heterostructures of graphene and its insulating analogue, h-BN, have been predicted to allow tuning of the bandgap and carrier mobility according to the carbon concentration [1]. Such hybrid structures have previously been synthesized by CVD on metal foils, and patterned using photolithography/reactive ion etching followed by a second growth step, before transfer onto insulating substrates [2]. In this research lateral graphene/h-BN heterostructures are grown on directly on 6H- and 4H-SiC (0001) by topological conversion of epitaxial graphene. Graphene can be chemically converted to h- BN upon heated exposure to ammonia (NH3) and boric acid (H3BO3) vapors, and the concentration of h-BN can be controlled by limiting the reaction time [3]. By x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), we observe the substitution of h-BN domains in the epitaxial graphene layer. The reaction nucleates at defects or functionalized carbon atoms which we confirm by Raman spectroscopy. This technique allows the growth of semiconducting hybrid atomic layers with tunable properties directly on a substrate suitable for device fabrication. [1] Wang, J., et. al., Small 9(8) 1373 (2013) [2] Liu, Z., et. al., Nat Nanotechnol 8(2) 119 (2013) [3] Gong, Y., et. al., Nat Commun 5 3193 (2014)

Summary:

Plenary / 81

Lab to Launch

Christine Charles1 ; Rod Boswell1 ; Wei Liang2 ; Luke Raymond2 ; Juan Rivas-Davila2 ; John Cater3 ; Nicholas Rattenbury3

1 The Australian National University 2 Stanford University 3 The University of Auckland

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Progress in satellite technologies is ongoing and eventually finds applications back on Earth. The global space industry is expecting significant growth based on cheaper launch capabilities and stan- dardised satellite platforms. Thousands of small satellites (such as CubeSats) are expected tobe launched over the next decade: a disruptive space revolution boosting Earth imaging, internet, global positioning and space weather forecast capabilities. Electric propulsion (EP) has been an innovative solution in a number of space missions but its scalability remains a challenge. Many mature or under

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development space propulsion systems could also benefit from more compact and efficient power supplies. Pocket Rocket is an Australian-born miniaturised electrothermal radio frequency plasma thruster which uses environmentally friendly propellant such as argon. A complete end-to-end small satellite industry — “Lab to Launch” — is now available wholly within the Trans Australasian Pacific region, thanks to the recent demonstration of Rocket Lab’s access to orbit. Groups at the Australian National University, Stanford University and the University of Auckland have joined forces to pave a path to space heritage for Pocket Rocket via the CubeSat platform. The aim is to improve the efficiency of a cold gas thruster in a single and effective manner by improving miniaturized power supplies and gas handling systems while training the next generation of students on radiofrequency, vacuum, power and plasma technologies. These innovations will help the future development of nano-satellite orbit control, attitude control, formation flying and docking capabilities. Most impor- tantly, a lot of interesting physics is left to be uncovered.

Summary:

Speaker Sessions and Seminars / 24

The Experimental Realization of Polyphony in Borophene

Lan Chen1

1 Institute of Physics, Chinese Academy of Sciences

Corresponding Author(s): [email protected]

The boom of graphene research, as well as the successful development of high-quality graphenefilms for industrial applications, has inspired the theoretical prediction and experimental discovery of a number of elemental two-dimensional (2D) materials. Boron (B), the one-electron-lacking neighbor of carbon in the periodic table, is identified by rather different chemistry as compared to C. Amixture of honeycomb units together with triangular units in two-dimensional (2D) sheets was predicted to be more stable. This gives rise to rich allotropy of boron, which is seen in the possibility ofits multiple phases in borophene. In this talk, I will introduce the experimental realization of borophene on Ag(111) surface by molecular beam epitaxy (MBE) growth in ultrahigh vacuum firstly. A few different phases relied on the substrate temperature during growth are confirmed. Furthermore, it is found that the crystalline symmetry of substrate can influence the morphology of borophene. The high quality borophene nanoribbons can be formed on an anisotropic substrate - Ag(110). By engineering the interface interactions and the charge transfer between substrate and borophene, we can realize the a purely honeycomb, graphene-like borophene on Al(111) surface. Theoretical calculations show that the honeycomb borophene on Al(111) is energetically stable. Remarkably, nearly one electron charge is transferred to each boron atom from the Al(111) substrate, in contrast to the little charge transfer in B/Ag(111) case. At last, I will show the angle-resolved photoemission spectroscopy measurements on borophene on Ag(111), which revealed Dirac cones in first Brillouin zone, proving the existence of Dirac fermions in borophene.

Summary:

Poster Session - Main Hall Tuesday / 37

Deposition of Si-incorporated a-C:H films on inner surface of microchannel

Junho Choi1 ; Kanju Kitamura1

1 The University of Tokyo

Corresponding Author(s): [email protected], [email protected]

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Hydrogenated amorphous carbon (a-C:H) film has attracted attention for its excellent properties including its high hardness, low friction, resistance to wear, abrasion, corrosion, and erosion, and transparency to infrared wavelengths. The industrial applications of a-C:H films include the surface reformation of various machine parts (such as engine parts, tools, and molds), electronics, optics, and biomedical engineering. However, most machine elements have complex three-dimensional structures, and the technology required to deposit a-C:H films on these complex structures has not yet been established. Previously, we have reported that the a-C:H coatings were successfully deposited on the inner surfaces of the microtrench, nanotrench and microchannel. However, there remains many issues in both film properties and uniformity on the inner surfaces. In this study, Si-incorporated hydrogenated amorphous carbon (a-C:H:Si) films were prepared on inner surface of 100-um-width microchannel by using a bipolar-type plasma based ion implantation and deposition. It was expected that the Si-incorporation increases sp3 bonds in a carbon network, resulting in a high hardness due to the amorphization of film. A mixture of toluene and tetramethylsilane gas was used as a precursor gas for the Si-incorporation. The microchannel was fabricated using a silicon plate. The distribution of thickness and hardness of films was evaluated by SEM and nanoindentation measurements, respectively, and the microstructures of films were evaluated by Raman spectroscopy. Furthermore, the behavior of ions and radicals was analyzed simultaneously by combining the calculation methods of Particle-In-Cell/Monte Carlo Collision and Direct Simulation Monte Carlo to investigate the coating mechanism for the microchannel. In a result, the a-C:H:Si films were successfully deposited on the entire inner surface of a microchannel. The deposition rate of the a-C:H:Si films on the inner surface of microchannel decreased as the Si content and the microchannel depth increased. It was found that the film hardness increased and the films became dense with increasing Si content.

Summary:

Poster Session B / 122

Neutron transmutation studies of Fe2O3

Richard ClementsNone ; Tunay Ersez1 ; Anton Stampfl2

1 ANSTO 2 Australian Nuclear Science and Technology Organisation

Corresponding Author(s): [email protected], [email protected]

Neutron transmutation, as a process, has traditionally been used to dope semiconductor materials in order to control the electrical conductivity and electronic structure of the valence and conduction band region which is vital for the function of a majority of semiconductor based technologies. A novel approach is introduced by the authors to use the nuclear process of neutron transmutation to effectively dope transition metal oxide materials. In the case2 ofFeTiO a number of dopants are produced, in particular Cr, Mn, and V. This cocktail of dopants can potentially be adjusted tosuit an application or area of study. This preliminary study documents the process involved in transmutation doping of a transition metal oxide and characterises some basic macroscopic properties such as magnetism, thermal conductivity, resistivity, etc., as well as fundamental properties in terms of electronic structure. Furthermore the effect of the irradiation on the virgin material, onbotha macroscopic and atomic level is presented.

Summary:

Poster Session B / 121

The electronic structure of FeTiO3

Richard ClementsNone ; Anton Stampfl1

1 Australian Nuclear Science and Technology Organisation

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Corresponding Author(s): [email protected], [email protected]

Magnetic transition metal oxide structures with ABO3 type stoichiometry offer a wide range of technologically important properties including ferroelectricity, ferromagnetism and colossal magnetoresistance, piezoelectricity, multiferroicity, and metal−insulator transitions. In the case of FeTiO3 its magnetic behaviour may be switched through use of a magnetic field which influences whether there is, or is not, some measurable magnetisation. This in part may be due to the possibility that FeTiO3 is unstable to energy-lowering structural distortions through cation-cation and cation-anion interaction. A photoemission study is presented that explores these ideas through the experimental and theoretical determination of the valence band structure as well as chemical states of the material after several processing steps. DFT calculations, Wien2k, are used to determine the chemical character of bonding and related to the various types of magnetic phase found in FeTiO3.

Summary:

Poster Session B / 107

A Synchrotron Investigation Of The Electronic Structure Of Lan- thanide Zirconates

Richard Clements1 ; Anton Stampfl2

1 School of Physics, University of New South Wales; Australian Centre for Neutron Scaterring, Australian 2 Australian Nuclear Science and Technology Organisation

Corresponding Author(s): [email protected], [email protected]

The lanthanide zirconates are of interest for use in inert matrix fuels and nuclear wasteforms. Foruse in these applications, the material’s structure must be as impervious as possible to radiation damage, and, therefore, its thermal, thermodynamic, and mechanical properties, at a basic sciences level, must be known to make any sort of real-world predictions. The rare earth zirconates are interesting model systems to explore such problems. In these materials the f-electrons may play a localized-valence decisive role in determining their thermo-mechanical properties making them an intriguing model for the interplay between the localised and delocalised valence nature of such oxide materials, the full understanding of which may also lead to novel material development. The f-electronic structure has historically proved difficult to model, however. We have synthesised the full series of lanthanide zirconates using solid state techniques. We have performed X-ray photoemission spectroscopy (XPS), valence band photoemission, and X-ray absorption near edge spectroscopy (XANES) with synchrotron radiation on a selection of the series. XANES has shown to be very sensitive to the Zr coordination environment. In conjunction with a density functional theory (DFT) model, we have determined the electronic structure and the role of the 4f electrons to the stability of these interesting materials.

Summary:

Poster Session - Main Hall Tuesday / 120

Electronic and vibrational studies of highly doped silicon.

Richard ClementsNone ; Tunay Ersez1 ; Anton Stampfl2

1 ANSTO 2 Australian Nuclear Science and Technology Organisation

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Corresponding Author(s): [email protected], [email protected]

Silicon remains the material of choice for much of the semiconductor industry that is used for a variety of functions in a plethora of devices. Doping plays an integral and vital part to the function of semiconductor material in modern devices, through the introduction of impurities (dopants) that control the electronic properties of the material. Silicon may be doped using a number of methods from those at the time of growth to those post-growth such as through diffusion or ion-implantation. Post-growth doping generally affects surface layers whilst during-growth methods produce homogeneous results throughout the bulk of the material. Neutron transmutation doping is a post-growth doping technique that employs a source of thermal neutrons (usually from a neutron research reactor) to change one element of the material to be doped into another via nuclear interaction. This type of doping does produce exceedingly homogeneous doping levels throughout the material. Natural silicon atoms are composed of three isotopes, 28Si (abundance: 92.23%), 29Si (abundance: 4.67%) and 30Si (abundance: 3.10%). When 28Si or 29Si absorb a thermal neutron, they are changed into other stable silicon atoms (28Si+n→29Si and 29Si+n→30Si). Research reactors configured to produce thermal neutrons do also produce higher energy neutrons. In particular the absorption of a fast neutron leads to the direct or indirect (via decay) production of Al or Mg isotopes. To suppress this secondary production which can lead to unwanted silicon properties a well thermalised neutron spectrum is obtained through judicious placement of the Si targets within the reactor. In the case of 30Si, thermal neutron capture leads to the unstable isotope 31Si, which undergoes beta decay. The product of this process is a phosphorus atom, 31P, resulting in n-type impurity doping in 30 31 31 0 the silicon: Si14 + n → Si14 → P15+ e−1+ν. This study focuses on the electronic and vibrational structure and lifetimes of highly n-type doped Si:P in the dopant range between 1019-1021 cm−3 using photoemission and neutron spectroscopy as well as thermoelectric relevant measurements. In particular the study focuses on the role phonon transport has on the lattice thermal conductivity in such a highly doped or degenerate semiconductor regime.

Summary:

Poster Session B / 116

Design and Manufacture of a High Resolution Orbital-Trapping Mass-Analyser for Secondary Ion Mass Spectrometry (SIMS)

Author(s): James Hood1

Co-author(s): Peter Cumpson 2

1 Newcastle University UK 2 Newcastle University

Corresponding Author(s): [email protected], [email protected]

High resolution mass spectrometry has revolutionised the identification of complex biological molecules and given rise to the “omics” revolution. However Static Secondary Ion Mass Spectrometry (SIMS) instruments typically still make use only of time-of-flight analysers. These still have many advantages, but the ability to send ions also to a very high mass resolution (>100,000) analyser when needed would be extremely useful. We have designed and fabricated a high mass-resolution orbital trapping analyser for Secondary Ion Mass Spectrometry (SIMS)[1]. A key issue is the precise machining and alignment of components of the ion trap. We perform finite difference method (FDM) simulations and ion trajectory calculations to establish the precision needed in manufacturing and aligning the trap. Machining of the high- precision mathematically-defined electrode surface was achieved through the use of hand-crafted Gcode segments. The ion trap and transfer assembly, once assembled, were characterised andkey

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dimensions measured, these then being used for SIMION[2] simulations of ion trajectories to check the operation of the device. [1] J C Hood and P J Cumpson, International Journal of Modern Engineering Research, 6 (2016) 76-83. (www.ijmer.com/papers/Vol6_Issue10/Version-2/J61027683.pdf ) [2] www.simion.com

Summary:

Poster Session - Main Hall Tuesday / 113

Multispectral Optical Imaging Retrofitted to XPS and ToFSIMS Instruments

Author(s): Peter Cumpson1 Co-author(s): Naoko Sano 2 ; Anders Barlow 3

1 Newcastle University UK 2 Nara Womens University 3 La Trobe University

Corresponding Author(s): [email protected], [email protected], [email protected]

All X‐ray photoelectron spectroscopy (XPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) instruments have optical cameras to image the specimen under analysis, and often to image the sample holder as it enters the system too. These cameras help the user find the appropriate points for analysis of specimens. However they seldom give as good images as stand‐alone bench optical microscopes, because of the limited geometry, source/analyser solid angle and ultra‐high‐vacuum (UHV) design compromises. This often means that the images displayed tothe user necessarily have low contrast, low resolution and poor depth‐of‐field. To help identify the different regions of the sample we have found it useful to perform multispectral imaging by illuminating the sample with narrow‐wavelength‐range light emitting diodes (LEDs). By taking an image under the illumination of these LEDs in turn, each at a successively longer wavelength, one can build up a set of registered images that contain more information than a simple Red–Green–Blue image under white‐light illumination. We show that this type of multispectral imaging is easy and inexpensive to fit to common XPS and ToF‐SIMS instruments, using LEDs that are widely available. In our system we typically use 14 LEDs including one emitting in the ultraviolet (so as to allow fluorescent imaging) and three inthenear infra‐red. The design considerations of this system are discussed in detail, including the design ofthe drive and control electronics, and three practical examples are presented where this multispectral imaging was extremely useful.

Summary: Multispectral optical imaging for XPS and ToFSIMS

Speaker Sessions and Seminars / 115

Rapid multivariate analysis of 3D ToF‐SIMS data: graphical processor units (GPUs) for large‐scale principal component analysis

Author(s): Peter Cumpson1 Co-author(s): Anders Barlow 2 ; Naoko Sano 3 ; Ian Fletcher 4

1 Newcastle University

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2 La Trobe University 3 Nara Womens University 4 Newcastle University UK

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

Principal component analysis (PCA) and other multivariate analysis methods have been used in- creasingly to analyse and understand depth‐profiles in XPS, AES and SIMS[1]. For large images or three‐dimensional (3D) imaging depth‐profiles, PCA has been difficult to apply until now simplybe- cause of the size of the matrices of data involved. We have developed two algorithms that improve the speed of PCA for large ToFSIMS datasets[2], and allow these datasets to be of unlimited size. We apply these to perform PCA on full 3D time‐of‐flight SIMS data for the first time[3]. An example is the processing of a 128 × 128 pixel depth‐profile of 120 layers, each voxel having a 70 439 value mass spectrum associated with it. This forms over a terabyte of data when uncompressed. Wehave implemented this algorithm on a PC having a graphical processor unit (GPU) card containing 2880 individual processor cores. This increases the speed of calculation by a factor of around 4.1 compared with what is possible using a fast commercially available desktop PC having central processing units alone, and full PCA of this terabyte of ToFSIMS data is performed in less than 7 seconds. We show a number of datasets and PCA results, including biological examples and 3D “tomographic” views of the PCA results[4]. [1] M S Wagner, D G Castner, Langmuir 17 (2001) 4649–4660 [2] P J Cumpson et al, Surface and Interface Analysis 47 (2015) 986–993 [3] P J Cumpson et al, Surface and Interface Analyis 48 (2016) 1328-1336 [4] www.youtube.com/watch?v=bUT0kYuad2E

Summary:

Speaker Sessions and Seminars / 117

Elemental 2D Materials Beyond Graphene

Yi Du1

1 University of Wollongong

Corresponding Author(s): [email protected]

Two-dimensional (2D) materials, which possess atomic or molecular thickness and infinite planar lengths, are regarded as a novel family of materials that have a great potential to transform modern electronics due to their unique nanostructures and electronic states, especially since the discovery of graphene, which possesses amazing functionalities such as high electron mobility and the quantum Hall effect at room temperature. Silicene, germanene, blue phosphorene, new allotropes of silicon, germanium and phosphorous, in 2D one-atom-thick honeycomb structures, could have the potential for promising applications in electronics, photonics, and the other related areas because they not only demonstrates essentially the same electronic properties as graphene, such as linear dispersion of the electron band and high Fermi velocity, but they also possess an energy gap at the Dirac point, stronger spin-orbital coupling (SOC) and inherent compatibility with the current semiconductor industry. In this talk, I will review our recent work on silicene, germanene, and blue phosphorene. By molecular beam epitaxial deposition, we successfully synthesized large-scale silicene, germanene and blue phosphorene layers on various substrates. The atomic honeycomb structures have been clearly demonstrated by scanning tunneling microscopy (STM). Their phonon properties and distinct electron- phonon coupling effects have been revealed by in-situ Raman spectroscopy. Electronic structures of silicene, germanene and blue phosphorene were demonstrated by scanning tunneling spectroscopy (STS) and angle-revolved photoemission spectroscopy (ARPES). The electronic dispersion, band gap, Fermi velocity, and surface reactive sites at the nano scale and atomic scale on the surfaces of these 2D elemental materials have been studied in details. We also successfully tuned their electronic properties by physical and chemical modulations.

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Summary:

Speaker Sessions and Seminars / 86

Electric Field Tuned Quantum Phase Transition from Topologi- cal to Conventional Insulator in Few-Layer Na3Bi

Mark Edmonds1

1 Monash University

Corresponding Author(s): [email protected]

Na3Bi in bulk form represents a zero-bandgap topological Dirac semimetal (TDS), but when confined to monolayer it is predicted Na3Bi is a 2D topological insulator with a bandgap of~300meV.1 Application of an electric field to few-layer Na3Bi has been predicted to induce a topological phase transition, opening up the possibility of creating new types of electronic switches known as ‘topological transistors’.2 However, opening a bandgap in TDS has proven elusive, as efforts to grow thin films have only succeeded in growing 15-20 nm films that remain zero-bandgap semimetals. In this talk I will discuss our efforts in growing epitaxial few-layer Na3Bi via MBE, and then subsequent measurements of the electronic structure and response to an electric field using scanning probe microscopy/spectroscopy and angle-resolved photoelectron spectroscopy. We demonstrate that few-layer Na3Bi is a 2D topological insulator with a bandgap >400 meV. Furthermore, via application of an electric field the bandgap can be tuned to semi-metallic and then re-opened as atrivial insulator with bandgap greater than 100 meV. The electric fields required to induce this transition are below the breakdown field of many conventional dielectrics, making the creation of a topological transistor based on a few-layer TDS within reach. 1 C. Niu, et al., Phys. Rev. B 95, 075404 (2017) 2 H. Pan, et al., Scientific Reports 5, 14639 (2015)

Summary:

Speaker Sessions and Seminars / 0

A Hybrid Hydrogen Storage System Based on Hollow Glass Mi- crospheres

Author(s): Christoph Eisenmenger-Sittner1

Co-author(s): Gerwin H. S. Drexler-Schmid 2

1 Vienna University of Technology 2 Austrian Institute of Technology

Corresponding Author(s): [email protected], [email protected]

The theoretical and experimental aspects of a hybrid hydrogen storage system consisting ofhydro- gen pressurized hollow glass microspheres (HGMS) and a hydride, e.g. NaBH4, will be discussed. Volumetric and gravimetric storage densities are assessed. Thermal aspects and hydrogen diffusion through glass are discussed. It is shown that hydrogen pressurized HGMS in combination with a hydride bear the potential to achieve storage densities up to 30-50 kg/m³. Hydrogen is stored by heating and pressurizing the spheres at approx. 85 MPa, forcing the gas into the spheres. Hydrogen is released by heating again to approx. 250℃. To reach this temperature the exothermal chemical reaction of NaBH4 with water, which produces hydrogen as a welcome by-product, is used. To pro- mote the reaction the HGMS (diameter approx. 20 µm) have to be coated with a catalyst.

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To produce the catalyst coating on the HGMS a special coating device based on non-reactive (for metals) and reactive (for non-metals) magnetron sputtering was designed. It provides continuous intermixing of the fragile spheres in a container by a combination of rotation and concussion. In the final design stage the coating mechanism can handle one liter of microspheres. The catalytic reaction is tested in a set-up which measures the released heat and amount of hydrogen. For Ru deposited on an adhesion promoting film of TiO2 the theoretical maxima of released heat and hydrogen could be achieved, thus rendering even the hydride based part of the system alone an interesting option for hydrogen storage.

Speaker Sessions and Seminars / 90

Scaling lab research to engage the manufacturing industry: a story of vacuum thin film coatings

Author(s): Drew Evans1 Co-author(s): Colin Hall 2 ; Kamil Zuber 1 ; Rodney Pratt 1 ; Marta Llusca 1 ; Sam Rudd 1 ; Eliza Switalska 1 ; Peter Murphy 1

1 University of South Australia 2 UniSA

Corresponding Author(s): [email protected], [email protected]

To remain competitive in a rapidly changing global market, many industries are looking at imple- menting new and innovative products. This sometimes requires engaging with scientific anden- gineering researchers to bring the latest discoveries to commercial products. The ultimate success of translating these discoveries into products will come from the ability to scale-up the fabrication processes from the lab into production. This presentation will provide an overview of the collaborative projects between university researchers and industry. Specifically focused on the scale-up research being undertaken by the Future Indus- tries Institute at UniSA in the area of thin film coatings. This research is aimed at scaling-up the thin film capabilities to create minimum viable product that can be tested by industry tomeetthe specifications set by their customers. In one example, our on-going partnership with the Malaysia Automotive Institute (through the MAI- UniSA Automotive Innovation Centre) has seen the design, build and commissioning of a pilot production flow coating plus inline magnetron sputtering system to deposit multilayer thin filmcoatings on plastic substrates up to 600x600mm in size. This capability allows for prototype product of light weight plastic glazing for electric vehicles to be tested. Such an approach to thin film materials research to manufacturing process design to partnered com- mercialisation of product with industry has in the past seen successful development of the world’s first plastic automotive mirror. In partnership with SMR Automotive, the UniSA team’s abilityto scale-up lab based processes to bridge the gap towards commercial manufacture was critical. As a result over 3 million of these products have been manufactured and exported to the global automotive industry. From this, the team have expanded their scale-up research to encompass thin film coating technology in the areas of defence, agriculture, renewable energy, and medical.

Summary:

Speaker Sessions and Seminars / 118

Surface defect engineering in semiconducting (photo)electrocatalyst

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Haifeng Feng1 ; Yi Du1 ; Weichang Hao2 ; Shixue Dou1

1 University of Wollongong 2 Beihang University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

Surface and near surface regions play a vital role in the determining catalytic activities of pho- tocatalysts and electrocatalysts. Firstly, catalytic reactions take place on the surface of catalysts, where the adsorption/desorption and charge transfer occur between catalyst and molecular. Sec- ondly, abundant surface mismatches, low coordinated ions or atoms, and defects are prevalent on the surface of a materials, which can strongly alter the electronic properties of catalysts and the adsorption/desorption behaviors of molecular on catalysts. Therefore, effective control of the species, concentration, and distributions of surface defects can modulate surface electronic structure and are of great significance in promoting the catalytic activities. Here, we show several approaches of modifying the electronic structure, and molecule adsorption/desorption behavior of various semiconducting (photo)electrocatalysts through manipulating surface defects. In addition, applications of scanning probe microscopies (SPM) techniques, including scanning tunneling microscope (STM) and atomic force microscope (AFM), in revealing the effects of surface defects on these catalysts are highlighted.

Summary:

Plenary / 125

X-ray dichroism studies of magnetic anisotropies in thin films

Atsushi Fujimori1

1 University of Tokyo

Corresponding Author(s): [email protected]

Magnetic anisotropy (MA) is one of the most important properties of ferromagnetic materials since it leads to magnetic hysteresis and coercive forces, which are necessary for permanent magnets and information storage devices [1]. MA arises from combined effects of spin-orbit cou-pling (SOC) and anisotropic electronic structure. Soft x-ray dichroism is a powerful method to investi-gate the anisotropic electronic and magnetic states of atoms in solids, at interfaces, and at surfaces, and the effect of SOC on them. Through measurements of x-ray magnetic circular dichroism (XMCD) with varying magnetic field direction including transverse geometry, we have studied the origin of MA in 3d transition-metal oxide (La1−xSrxMnO3) thin films whose MA is controlled by epitaxial strain [2], and in 3d transition metal-heavy metal alloy (L10-ordered FePt) thin films showing strong perpendicular MA [3].

In the transition-metal-oxide thin films, epitaxial strain from the substrate is shown to induce anisotropic distribution of spin-polarized electrons [2], which leads to MA through the orbital magnetic moment anisotropy (OMA). As a reverse process of the strain-induced MA, we have detected a fieldinduced anisotropic electron distribution using x-ray magnetic linear dichroism (XMLD). In the transition metal-heavy metal alloy thin films, the relationship between the MA and OMA, well-known Bruno relationship, is shown to breakdown [3], and the anisotropic distribution (i.e. quadrupole moment) of spin-polarized electrons, which is unrelated with OMA, is shown to make dominant contribu-tions to MA.

This work has been done in collaboration with G. Shibata, K. Ikeda, Y. Nonaka, Y. Takahashi, K. Ishi-gami, T. Harano, T. Kadono, T. Koide, K. Amemiya, M. Sakamaki, Y. Takeda, M. Suzuki, N. Kawamu-ra, T. Seki, K. Takanashi, M. Kitamura, M. Minohara, K. Yoshimatsu, H. Kumigashira and A. Tanaka.

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References [1] M. J. D. Coey, Magnetism and Magnetic Materials (Cambridge, 2009). [2] G. Shibata, A. Fujimori et al., npj Quantum Mater. 3, 3 (2018). [3] K. Ikeda, A. Fujimori et al., Appl. Phys. Lett. 111, 142402 (2017).

Summary:

Poster Session B / 65

Study of hydrogen absorption and desorption properties of oxygen- free Pd/Ti thin film as a non-evaporable getter (NEG) coating by using nuclear reaction analysis (NRA)

Author(s): Masuaki Matsumoto1 Co-author(s): Tomohiro Okada 1 ; Tetsuya Miyazawa 2 ; Kazuhiko Mase 3 ; Ayako Hashimoto 4 ; Markus Wilde 5 ; Katsuyuki Fukutani 5

1 Tokyo Gakugei University 2 SOKENDAI 3 KEK 4 National Institute for Materials Science 5 Institute of Industrial Science, University of Tokyo

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Absorption and desorption properties of hydrogen for the oxygen-free Pd/Ti thin film was studies by using 1H(15N,αγ)12C nuclear reaction analysis(NRA) and thermal desorption spectroscopy (TDS). The oxygen-free Pd/Ti film was developed as a new non-evaporable getter (NEG) coating, whichis expected to keep high pumping speed after many cycles of air-vent and activation by heating [1]. It is expected that non-activated dissociation of H2 on the Pd surface and diffusion into Ti film can occur at room temperature. It is also expected that hydrogen can be desorbed from Ti film through Pd at lower temperature than the conventional NEG. Since TiO2 works as a hydrogen barrier, it is important that Pd/Ti thin film is produced under oxygen free condition, which is realized by sublimation of Ti and Pd on stainless steel (SS304) in ultra-high vacuum (UHV) . Pumpdown curves of the Pd/Ti film coated SS304 was measured and the pumping speed was confirmed to be almost constant under several venting-pumpdown-baking cycles. This coating is expected to overcome a weakness of the conventional NEG, whose pumping speed is degraded rapidly by repeated heating-venting cycles. Since H2 is main residual gas under UHV condition, it is important to measure hydrogen absorption/desorption properties of the Pd/Ti thin film precisely [1]. The NRA using 1H(15N,αγ)12C is suitable for investigating depth profile of hydrogen concentration quantitatively. The narrow energy resonance at 6.385 MeV of nuclear reaction of 15N with hydrogen is deteriorated by Doppler-broadening and struggling effect, but high resolution (a few nm) depth profiling of H can be achieved near the surface. The Pd(6 nm)/Ti(12 nm)/SS304L (8mm×8 1 mm) sample was prepared in a UHV chamber, in which film thickness was estimated by transmission electron microscopy (TEM). The energy dispersion X-ray spectroscopy mapping using TEM (TEM-EDX) shows that the layers of Pd and Ti are separated. The NRA spectrum obtained just after evacuation revealed that the small amount of H exists at the Pd surface and in the Ti thin film. H in the Ti film increased 20 times by exposing to 10000 LH2. A part of H2 may be dissociated at the W filament of the vacuum gauge. By the quantitative analysis, it is suggested thatTiH1.27 is produced in the whole Ti layer. Though the density of H in the Ti film did not change by heating below200 ◦C, it rapidly decreased above 200 ◦C. Repeated cycles of absorption at room temperature and desorption by annealing at about 240 ◦C was possible. However, H absorption ability was lost, once the sample was annealed above 500 ◦C.

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[1] T. Miyazawa, K. Tobishima, H. Kato, M. Kurihara, S. Ohno, T. Kikuchi and K. Mase, Vac. Surf. Sci. 61, 227 (2018).

Summary:

Speaker Sessions and Seminars / 102

Adsorption and absorption of hydrogen in Titanium dioxide

Katsuyuki Fukutani1

1 University of Tokyo

Corresponding Author(s): [email protected]

Titanium dioxide (TiO2) surfaces are of interest and importance in both physical and chemical aspects including photocatalytic H2 generation, hydrogen sensors, and two-dimensional electron gas formation. Titanium dioxide reveals polymorphism of rutile and anatase. Upon interaction with TiO2 surfaces, hydrogen might adsorb on the surface and diffuse into the interior of TiO2, which significantly affects the electronic structure of TiO2. In these regards, interaction of hydrogen with TiO2 surfaces is of particular importance. We have studied the hydrogen adsorption and absorption in the rutile TiO2(110) and anatase TiO2(101) surfaces with nuclear reaction analysis (NRA) and ultraviolet photoemission (UPS). Whereas the former allows us to quantify hydrogen in the sample in a depth-resolved manner [1], the latter provides us with the information on the electronic occupied and unoccupied states. When the nearly stoichiometric surfaces of rutile TiO2(110) and anatase TiO2(101) are exposed to atomic hydrogen, NRA shows adsorption of hydrogen with a coverage of about 0.5 monolayer [2]. Concomitantly, a decrease in the work function and downward band-bending are observed by UPS suggesting electron transfer from adsorbed hydrogen to the substrates. Upon annealing the samples, the hydrogen amount near the surface is reduced without desorption indicating that hydrogen undergoes diffusion into bulk. When the rutile TiO2(110) surface is exposed to a hydrogen ionbeamat 500 eV, an enhanced hydrogen concentration within 10 nm from the surface is detected as compared to the exposure to atomic hydrogen along with an enhanced band-bending. UPS using ultraviolet laser reveals hydrogen-induced features in the unoccupied states, which could be related to photocatalytic activity. References [1] M. Wilde, K. Fukutani, Surf. Sci. Rep. 69, 196 (2014). [2] K. Fukada et al., J. Phys. Soc. Jpn. 84, 064716 (2015).

Summary:

Speaker Sessions and Seminars / 274

Neutron Imaging Facility DINGO targetting new fields of research with high resolution upgrade

Ulf Garbe1

1 ANSTO

Corresponding Author(s): [email protected]

The new neutron radiography / tomography / imaging instrument DINGO is operational sinceOcto- ber 2014 to support research at ANSTO. It is designed for a broad national and international scientific

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user community and for routine quality control for defence, industrial, cultural heritage and archae- ology applications. In the field of industrial application it provides a useful tool for studying cracking and defects in concrete or other structural material. Since being operational we gathered experience in various scientific fields, with industrial applications and commercial customers demanding beam time on DINGO. The measured flux (using gold foil) for an L/D of approximately 500 at HB-2is5.3x 107 [n/cm2s], which is in a similar range to other facilities. A special feature of DINGO is the in-pile collimator position in front of the main shutter at HB-2. The collimator offers two pinholes witha possible L/D of 500 and 1000. A secondary collimator separates the two beams by blocking one and positions another aperture for the other beam. The neutron beam size can be adjusted to the sample size from 50 x 50 mm2 to 200 x 200 mm2 with a resulting pixel size from 10µm to ~100µm. First results on 3D-printed functional ceramics tomography and porosity analysis on carbon fibre object will be preseted. A further upgrade available begin of next year will deliver a pixel size of 2-3µm wit a custom made lens camera setup in combination with an isotope enriched Gadox scintillation screen. In addition we will present an outlook into a real neutron microscope magnifying the neutron image with magnetic lenses targeting the sub micron area. This new imaging instrument concept is a potential candidate for a second guide hall planned at ANSTO.

Summary:

Plenary / 124

Using light, high energy radiation and theranostic nanomaterials to engineer interactions with biological systems

Ewa Goldys1

1 University of New South Wales

Corresponding Author(s): [email protected]

The Australian Research Council Centre of Excellence for Nanoscale Biophotonics draws onkeyad- vances of the 21st century, nanoscience, and photonics to help understand life at the molecular level. This talk will focus on next-generation nanotechnologies developed in our Centre for probing, imaging and interacting with the living systems. These address the key challenges of ultrasensitive detection of key analytes in real environments, molecular complexity, and the requirement for interventions in deep tissue. Theranostic nanomaterials simultaneously facilitate diagnostics including molecular sensing and active interventions required in therapies. I will discuss how our nanomaterials can produce light and interact with cells when stimulated with high energy radiation, and how this interaction can be quantified. The crossing of length scales inherent in radiotherapy combined with such nanomaterials forms powerful building blocks for innovative cancer treatments.

Summary:

Speaker Sessions and Seminars / 91

Electronic Structure and Electron Dynamics in Single-Layer Tran- sition Metal Dichalcogenides

Antonija Grubisic-Cabo1

1 Monash University

Corresponding Author(s): [email protected]

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The size of a band gap determines the suitability of a material for use in different applications suchas computers or in solar cells. In the case of artificial two-dimensional (2D) materials, such as graphene or single-layer (SL) transition metal dichalcogenides (TMDCs), electronic properties, including the band gap, are drastically different from their parent compounds, where dimensionality is not reduced. The electronic properties of 2D materials do not only depend on the material, but also onitsen- vironment, for example, the substrate it is placed on. By changing the dielectric properties of the substrate or the carrier concentration in the material, the band gap size can be modified. Besides control of the band gap, control of the spin- and valley-degrees of freedom has been suggested as a new, potential tuning knob for carrier dynamics, and SL TMDCs, such as SL MoS2 and WS2, are particularly promising candidates for new spin- and valley-tronic devices. This is due to the breaking of the inversion symmetry in their crystal lattice, a strong spin-orbit coupling, and a direct band gap at the K and K’ valleys in their electronic structures. In order to obtain information about ultrafast carrier dynamics and valley-degrees of freedom, it is necessary to probe the samples in a manner that can provide both time and angular resolution. The time- and angle-resolved photoemission spectroscopy (TR-ARPES) technique provides exactly that. TR-ARPES is, however, limited by the technical requirement for high photon energies, since the interesting part of the aforementioned materials’ electronic structures is located at the 2D Brillouin zone boundary. This technical limitation was recently overcome with the arrival of ultrafast high harmonic laser sources. These sources can be used to directly access the size and character ofthe electronic band gap in a semiconducting 2D material, while in the case of 2D metallic layers, the effect of the low dimensionality on electronic instabilities such as charge density waves andsuper- conductivity can be investigated. This talk will cover single layers of MoS2, WS2 and TaS2 epitaxially grown on Au(111), Ag(111)and graphene. Furthermore, technical requirements, the experimental system and growth procedures will be presented, along with the future experimental directions.

Summary:

Speaker Sessions and Seminars / 76

The Magnetic Properties of Individual Atoms/Molecules on Solid Surfaces

Guo HaimingNone

Control over charge and spin states at the single atom and molecule level is crucial not only for a fundmental understanding of charge and spin interactions but also represents a prerequisite for development of spin tronics. Recently, we demonstrate that the Kondo resonance of manganese phthalocyanine (MnPc) molecules can be reversibly switched via a robust route through chemical absorption and desorption of a single hydrogen atom, and further the site-dependent g factor mapping was revealed within a dehydrogenated-MnPc molecule within intramolecular resolution. The modulation of magnetic properties and Kondo effect of magnetic adatoms on graphene layer wasalso studied, and we show the first discovery of a Kondo effect caused from a magnetic impurities doped in graphene layer in experiment. Finally I will present the investigation of different inter-atomic spin interactions of artificial Mn nanolusters registered on graphene with magnetic field dependent inelastic spin excitation spectroscopy. All the dimers observed exhibit an antiferromagnetic singlet ground state and spin transitions from singlet to triplet states, but their AFM coupling strength shows unique dependence on their site registration on the graphene template. More intriguing spin coupling can be found in graphene mediated non-collinear Mn trimer. The exchange energies cannot be understood by direct spin exchange mechanism, but suggesting the non-local Ruderman-Kittel- Kasuya-Yosida (RKKY) indirect spin exchange mechanism through substrate modulation, which has not yet been achieved in graphene so far.The works open up new opportunities to access local spin properties and quantum states at the ultimate molecular limit.

*Presenting and Corresponding Author: [email protected] 1) J. D. Ren, H. M. Guo, and H. J. Gao et al, Phy. Rev. Lett. 119, 176806 (2017) 2) J. D. Ren, H. M. Guo, and H. J. Gao et al, Nano Lett. 14, 4011 (2014) 3) J. D. Ren, X. Wu, and H. M. Guo et al, Appl. Phys. Lett. 107, 071604(2015)

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4) L. W.Liu, K. Yang, and H. J. Gao et al, Sci.Rep.3, 1210 (2013) 5) L. W. Liu, K. Yang, and H. J. Gao et al, Phys. Rev. Lett. 99, 106402 (2015)

Summary:

Speaker Sessions and Seminars / 106

Sulfides, Surfaces and Synchrotrons

Sarah Harmer1

1 Flinders University

Corresponding Author(s): [email protected]

The physical and chemical properties of sulfide mineral surfaces and their interactions with aqueous environments and microbes, is crucial to minerals processing. Over the past 30 years surface analysis techniques including X-ray photoelectron spectroscopy (XPS), Auger Electron Spectroscopy (AES), Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Atomic Force Microscopy (AFM) and X-ray absorption Spectroscopy (XAS) have been used to elucidate the surface properties of sulfide minerals at selected stages during processing. Their use is now commonplace and has driven interest for further development of advanced in and ex situ nano-spectroscopic techniques. Nanospectroscopic imaging techniques have provided the opportunity to investigate the effects of mineral heterogeneity and interaction of microbes on the distribution of surface chemical products during dissolution. A prototype Electrochemical Nanoreactor, for high resolution spectroscopic imaging in a hydrated and controlled electrochemical state has been developed and used to study the growth of Cu dendrites and the dissolution of pyrite and chalcopyrite in the presence of Af. The results support the preferential attachment of bacteria to pyrite and the modification of its surface with polysaccharides. The technique shows promise for applications in in-situ geomicrobiological and electrochemical research.

Summary:

Speaker Sessions and Seminars / 95

Molecular layer formation on cooled sapphire mirrors in KAGRA Japanese gravitational wave observatory

Author(s): Kunihiko Hasegawa1

Co-author(s): Tomotada Akutsu 2 ; Yuki Inoue 3 ; Nobuhiro Kimura 4 ; Toshikazu Suzuki 1 ; Takayuki Tomaru 4 ; Ayako Ueda 4 ; Yoshio Saito 1 ; Shinji Miyoki 5

1 ICRR, University of Tokyo 2 NAOJ 3 Academia Sinica 4 KEK 5 ICRR, the University of Tokyo

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

KAGRA is Japanese gravitational wave observatory which is located in the underground site to reduce seismic motion. In order to decrease the mirror thermal fluctuation, four antenna mirrors have to be cooled down. To achieve 20K for mirror temperature, sapphire was chosen as a material of

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cooled mirrors and their suspension components in the final vibration reduction stage because of its advantages of thermal conductivity and high mechanical Q value at cryogenic temperature. The requirements of KAGRA vacuum pressure is 1×10^(-7) Pa, or lower, to avoid refractivity fluctuation due to vacuum residual gases. In order to achieve above requirement in huge volume/area of vacuum chambers and ducts, surface processing for reducing outgassing was applied and materials for use as large suspension systems are carefully chosen. Furthermore, by cooling down, cryostat works as cryo-pump so pressure around cryostat becomes quite low. Recently, it was revealed that the vacuum residual molecules were adsorbed on cooled sapphire mirrors and finally many numbers of molecules form an adlayer. This molecular adlayer worksasa kind of optical coating and changes mirror reflectivity depending on its thickness. To investigate the molecular layer formation in KAGRA, a small optical cavity, having high finesse, was installed in KAGRA cryostat and its finesse was monitored for 35 days.

Summary:

Speaker Sessions and Seminars / 146

Quantum-Based Pascal and The End of Mercury Manometers

Jay Hendricks1

1 NIST

Corresponding Author(s): [email protected]

New methods of pressure and vacuum realization that are based on quantum calculations are currently under development. This is exciting in that it fits with the current SI-redefinition paradigm, that if a new technique relies upon a quantum property, measurement, calculation, or invariant of nature, then this technique can have served as a primary standard. Standards built this way are then directly tractable to the SI and will not itself require re-calibration. For the Pascal, a Fixed Length Optical Cavity (FLOC) and methods the enable the FLOC to be primary, including a Variable Length Optical Cavity (VLOC) will be discussed. These new methods operate by measuring the gas pressure though the interaction of light with the atomic or molecular properties of the gas and have enabled a new quantum-based pressure standard. Development of these new standards will enable the elimi- nation of mercury manometers, a standard that has been in use for four centuries. The talk will cover the current status of the effort by National Metrology Institutes to re-define standards through the use of quantum based measurements, and will connect current NIST this efforts to the coming SI- Redefinition. The talk will also briefly update activates to develop a Cold Atom Vacuum Standard (CAVS) which will enable a quantum-based vacuum standard capable of measuring extreme vacuum (XHV). Evangelista Torricelli invented the mercury in 1643, and while he did not realize it at the time, started a new field of vacuum technology which lead to the explosion of technology thatlead to the modern national vacuum societies of today!

Summary:

Speaker Sessions and Seminars / 224

Studying Structure at the Liquid/Liquid Interface by Neutron and X-ray Scattering.

Stephen Holt1

1 Australian Nuclear Science and Technology Organisation

Corresponding Author(s): [email protected]

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The investigation of structure at the liquid/liquid interface is of prime importance in anumberof physico-chemical areas both fundamentally and practically. This presentation will focus on x-ray and neutron scattering approaches to studying structure and molecular conformation at planar oil/water interfaces. The oil/water interface is crucial to many industrial systems, for example emulsions (food, cosmetics, drug delivery and others), chemical extraction (both aqueous to organic and the subsequent back extraction). After outlining technical aspects and alternative model systems I will discuss our current workon tailorable nanoemulsions (TNE) for drug delivery. The TNEs consist of an oil in water emulsion where the interface is stabilised by a rationally designed single alpha helix peptide (AM1). To the AM1 stabilised emulsion a related four-helix peptide (DAMP4) is added. The DAMP4 can be linked to a range of biologically functional elements including antibodies or protein resistant molecules. The arrangement of the AM1 and DAMP4 at the oil/water interface and competition between the two species are important questions, the answers to which help to guide the TNE design. Furthermore, the presentation, conformation and orientation of the antibody into the aqueous phase impacts upon the TNE design and ultimately activity.

Summary:

Speaker Sessions and Seminars / 142

Performance of ZnGa2O4 deep ultraviolet photodetectors

Ray-Hua Horng1 ; Si-Han Tsai1 ; Huang Chiung-Yi 1

1 National Chiao Tung University, Institute of Electronics

Corresponding Author(s): [email protected], [email protected]

A single-crystalline ZnGa2O4 epilayer was successfully grown on c-plane (0001) sapphire substrate by MOCVD for application as high performance metal-semiconductor-metal (MSM) visible-blind deep-ultraviolet (DUV) photodetector (PD). The optimized growth parameters for the growth pressure and growth temperature were 15 torr and 650 oC, respectively. The result presented here demonstrate the performance of as grown and annealed at 800 oC in a nitrogen environment for 1 h ZnGa2O4 epitaxial films photodetectors. Compared to as grown ZnGa2O4 film improved UV properties of annealed ZnGa2O4 film were observed. It was found that as-grown films exhibit the highest density of cation-anion pair defects, which could contribute deep trapping centers that increases the generation current or trap assisted leakage current delaying the response and recovery times of as-grown PD devices. However, post-annealing provides sufficient energy to reduce the cation-anion pair defects in the as-grown samples to repair each other. The magnitude of the pho- tocurrent and the rise time are found to increase considerably with decrease number of trap levels. At 5 V bias voltage, the annealed ZnGa2O4 PD shows superior performance with an extremely low dark current of 1 pA, a responsivity of 86.3 A/W corresponding, cutoff wavelength of 280 nm, a highest DUV-to-visible discrimination ratio up to 107 upon 233 nm DUV illumination. The rise time of annealed ZnGa2O4 PD was 0.5 s and PD has been shown a relatively slow decay time of 0.7 s. In this study, our approach provides a simple and controllable method to fabricate single crystalline ZnGaO films based high-performance DUV photodetectors, which has been rarely reported.

Summary:

Speaker Sessions and Seminars / 141

Growth and fabrication of molybdenum disulfide devices

Wang Hsiang-Chen1

1 National Chung Cheng University

Corresponding Author(s): [email protected]

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The two-dimensional layered material MoS2 is the most common transition metal dichalcogenide. The bulk MoS2 is a semiconductor material with an indirect energy gap (about 1.3 eV) withstrong sulfur and molybdenum metal in the plane of the monolayer valence bond function, and there is a very weak Van der Waals force between layers. The monolayer MoS2 has a direct energy gap (about 1.9 eV) and an N-type semiconductor material with strong light emission characteristics, high planar electron mobility and tough mechanical properties, making it applicable applies to transistors, gas sensing detector, photodetector, battery, optoelectronic components. In the past, our laboratory successfully used CVD method to grow graphene and molybdenum disulfide films, combined with the hyper-spectral imaging for the optical properties detection of a few layers of thin film. On the other hand, we also have been successfully fabricated some nanostructures of cuprous oxide and zinc oxide. These nanostructures are made of anodized aluminum and two-beam interference technology. We expect to combine two-dimensional materials and semiconductor device fabrication into biochip through the use of biochips. Using biosensors based on semiconductor material synthesis and micro- nanostructure technology, we hope to develop a low-cost and fast response time, simultaneous detection of biosensors simple program. Recent studies have found that the change of surface stress of transition metal dichalcogenide will change its optical properties such as energy gap, absorption spectrum, even the electron mobility and induced magnetic force. The changes of these properties will enhance the optoelectronic performances of the transition metal dichalcogenide device and material properties. In this study, we will design the best transition metal dichalcogenide devices based on the previous research results. We will apply these devices to biological, gas, and photoelectric sensors and discuss the relationship between the photoelectric characteristics and stress distribution of various devices, and through the deep learning technology to enhance the photoelectric efficiency of devices.

Summary:

Speaker Sessions and Seminars / 140

Diamond-Edge Gaskets for the Ultrahigh Vacuum Systems

Gao-Yu Hsiung1

1 National Synchrotron Radiation Research Center, Taiwan

Corresponding Author(s): [email protected]

A special designed aluminum diamond-edge (DE-) gasket was applied to seal the aluminum vacuum chamber on the diamond-edge flat (DEF-) flange, instead of the traditional assembly of the aluminum metallic gasket with the ConFlat (CF-) flange, can achieve the ultrahigh vacuum (UHV) specified leak rate < 1x10-10 Pa∙m3/s and the ultimate pressure of < 10-8 Pa. Since both the DE-gasket and the DEF-flange, made of A1050 and A6061T6 aluminum alloys respectively, are manufactured bythe CNC machining with the special tools, therefore the cross section of the flanges and gaskets can be made either in circular shape or in other non-circular shapes, e.g. the rectangular, racetrack, or elliptical shapes. For the ultrahigh vacuum systems, the chambers made of aluminum alloys with the DEF-flanges and the aluminum DE-gaskets sealing can be customer-designed and machined easily. No further cleaning for the aluminum chambers is necessary if adopting the oil-free ethanol CNC machining process. The features of the DE-gasket include: (1) flexible dimensional changes from smaller to larger or from uniform to non-uniform, (2) flexible cross section changes from circular to non-circular, (3) wide range of vacuum extends from 1 atm to the ultrahigh vacuum, (4) more tolerance of mounting accommodates the DE-gasket to the flat DEF-flange, (5) DE-gasket can be reused few more cycles if still compressible. The assembly of the DE-gasket and the DEF-flanges provides reliable sealing-capabilities, flexible and easier machining properties, that is applicable for all the UHV systems including the aluminum ones. Several experimental results will be addressed in this presentation.

Summary:

Speaker Sessions and Seminars / 93

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Observation of a resonant-type ground state in graphene intercalated with cerium

Choongyu Hwang1

1 Pusan National University

Corresponding Author(s): [email protected]

The interaction between a magnetic impurity and metallic background provides a key to understand many-body interaction and its effect on the electro-magnetic properties of a material. Such aninter- action leads to the formation of a resonant-type many-body ground state, so-called Kondo resonance, that is enhanced at low temperatures. We investigate temperature-dependent electron band structure of graphene intercalated with cerium, which provides metallic electrons and localized 4f electrons, respectively. Cerium intercalation induces new spectral weight in graphene band structure that becomes stronger at low temperature, which is attributed to the formation and development of the new many-body ground state.

Summary:

Speaker Sessions and Seminars / 175

Micro- and nano-tomography with nanoparticles

Yeukuang Hwu1

1 Institute of Physics, Academia Sinica

Corresponding Author(s): [email protected]

The new generation synchrotron and X-ray Free Electron Laser facilities mark an important mile- stone on the development of x-ray science. Two examples will be presented to illustrate the bright potential of x-rays. The extremely bright hard-x-rays provide a unique opportunity to synthesize metal nanoparticles of high quality with high throughput. On the other hand, the same high brightness x-ray photons enable the phase contrast imaging and transmission x-ray microscopy of unprecedented performance. The nanoparticles synthesized by x-rays and the x-ray characterization already impacted life science by tackle important questions, such as the tumor related micro-angiogenesis. With the capability to characterize quantitative all the structural factor of the microvasculature of complete tumor region or an organ, aided with the innovative use of nanoparticles, we could conclude that the phenotype dependent tumor angiogenesis in mouse glioma models. Using the excellent performances of the SACLA (RIKEN/HARIMA, Japan) x-ray free electron laser (X-FEL), coherent diffraction imaging (CDI) was successfully implemented to image individual liposome particles in water, with or without inserted doxorubicin nanorods. In spite of the low cross section of the original ingredients, the diffracted intensity of drug-free liposomes was sufficient for spatial reconstruction yielding quantitative structural information. For particles containing doxorubicin, the structural parameters of the nanorods can be extracted from CDI. Furthermore, the measurement of the electron density of the solution enclosed in each liposome provides direct evidence of the incorporation of ammonium sulphate into the nanorods. This is an important test for extending the X-FEL analysis of individual nanoparticles to low cross-section-systems in solution, and also for its potential use to optimize the manufacturing of drug nanocarriers.

Summary:

Plenary / 72

Incorporating nanomaterials into semiconductor technologies

Francesca Iacopi1

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1 University of Technology

Corresponding Author(s): [email protected]

Semiconductor technologies are at the basis of most miniaturized systems available to us, whether in the form of microprocessors, or micro and nano -sensors, miniaturised cameras and acoustic systems, etc. Such systems are made of integrated circuits and nanoscale components built in parallel on a semiconductor substrate, following a sequence of hundreds of subtractive, thin -film based processes. Over several decades, semiconductor technologies could afford to use only a few well -known materials, such as silicon as the semiconductor, silicon dioxide as the insulator, and generally aluminium for the wiring. In more recent times though, this very conservative industry has been forced to introduce a wide range of new materials to enable the downscaling of feature sizes as dictated by Moore’s Law. Nanotechnology, and specifically nanostructured materials, have already or are being introduced in semiconductor technologies, while striving towards the ultimate miniaturisation. Nev- ertheless, introducing a new material is anything but a straightforward process, due to the strong constraints by chemical and particle contamination, process compatibility, thermal and mechanical stability, quality, and uniformity requirements of the processes in semiconductor manufacturing, as they dictate yield, performance and reliability of a product. The bottom -up approach most often needed for the synthesis of nanomaterials, the intrinsically higher variability and other difficulties proper to scaling up their synthesis over large areas, as well as considerations related to the compatibility or materials and processes are only some of the bottlenecks to the incorporation of nanostructured materials in semiconductor technologies. We will review the history of successful and unsuccessful attempts to integrate 1D (nanowires) and2D (graphene) materials as examples. We will conclude that in order for nanomaterials to be meaning- fully incorporated in semiconductor technologies, their synthesis needs to be designed and informed from the start by the requirements and constraints of semiconductor manufacturing.

Summary:

Speaker Sessions and Seminars / 82

What is Brilliant and BRIGHT at the AUstralian Synchrotron

Michael James1

1 ANSTO

Corresponding Author(s): [email protected]

The 3 GeV Australian Synchrotron is one of Australia’s premier research facilities and represents one of the biggest single investments in scientific excellence in the nation’s history. Following its operation on behalf of the State of Victoria, the Australian Synchrotron is now owned and operated as part of the Australian Nuclear Science and Technology Organisation (ANSTO). While the majority of ANSTO’s operations are in Sydney, the Australian Synchrotron is located in the Melbourne suburb of Clayton and is staffed by ~140 scientists, engineers, technicians, and support staff. The Australian Synchrotron has become an integral part of the Australian and New Zealand research landscape. The facility has now supported over 40,000 user visits to its 10 operational beamlines, resulting in scientific research that has already had a significant and lasting impact. The facility generates more than 500 peer reviewed journal articles annually, with 20% appearing in the world’s leading journals. Moving to Commonwealth operation has allowed provision of funds to significantly refurbish our existing suite of beamlines and machine systems. This presentation will highlight some of the major development projects currently underway at the Australian Synchrotron, as well as indicate the capabilities and activities of several of the current suite of operational beamlines. Looking forward, the facility has commenced the next phase of Beamline construction, with the development of eight new beamlines. This expansion of the Australian Synchrotron – called the “BRIGHT” program – will deliver a substantial set of new beamline capabilities to complement the existing excellent instrumentation at the facility.

Summary:

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Poster Session B / 84

Rapid thermal annealing effect on characterizations of CNW by chemical vapor deposition

Soojung JangNone ; Seung-cheol YooNone ; Sejin JungNone ; Taehwan LeeNone ; Hyunil KangNone

Corresponding Author(s): [email protected]

In this study, CNW(Carbon Nanowall) is grown on a silicon substrate by using microwave PECVD(Plasma enhanced chemical vapor deposition), and structural heat treatment of CNW using RTA(Rapid Ther- mal Annealing) The results of analyzing the characteristics and the electrical characteristics are shown. Using microwave PECVD, CNW was grown for 15 minutes on a silicon substrate at 1300W and 600℃. Then, the grown CNW was subjected to a heat treatment according to temperatures of 600℃, 700℃, 800℃ and 900℃. using RTA. We analyzed the structural characteristics and electrical characteristics of CNW fabricated and CNW not heat treated. In order to analyze structural characteristics, we used EDS(Energy dispersive X-ray spectroscopy) and Raman spectroscopy attached to FE-SEM(Field Emission Scanning Electron Microscope), SPM(Scanning Probe Microscopy), and FE-SEM. The cross section of CNW was analyzed by cross-section FE-SEM. The surface ofCNWwas analyzed with SPM and surface FE-SEM. Utiliz ing Raman spectroscopy, after confirming the growth of CNW, the crystal of CNW was confirmed by ID/IG ratio. Using the EDS, the element weight% and atomic% of CNW were measured, respectively. A Keithley 2400 instrument was used to analyze the electrical properties. Current and voltage of CNW were measured and resistance was calculated. CNW grown on a silicon substrate was compared with the structural characteristics and electrical characteristics of the heat treated using RTA unless heat treatment was performed.

Summary:

Speaker Sessions and Seminars / 17

Determining the effect of substrate cleaning on the solution stability of plasma polymer films

Karyn Jarvis1 ; Sally McArthur1

1 Swinburne University of Technology

Corresponding Author(s): [email protected], [email protected]

Plasma polymerization modifies surfaces via the deposition of a thin film possessing specific functional groups. The organic monomer is introduced into the low pressure chamber as a vapour, frag- mented via radio frequency and deposited onto all surfaces in contact with the plasma. Commonly used monomers such as octadiene, allylamine and acrylic acid enable the deposition of hydrocarbon, amine and carboxylic acid terminated surfaces respectively. Surface cleaning prior to the deposition of thin films is frequently carried out to improve film adhesion. The use of plasma polymer films in biomedical applications has increased the demand for coatings suitable for use in physiological conditions. Significant changes in film properties in aqueous conditions have serious implications on the incorporation of these films in biomedical technologies and devices. In this study, silicon wafer substrates were cleaned by several different methods prior to the deposition of plasma polymerized thin films to investigate the influence of substrate cleaning onfilm stability in aqueous solutions. The substrates were used untreated or cleaned by liquid sonica- tion, UV/ozone cleaning or air plasma. X-ray photoelectron spectroscopy (XPS) and contact angle measurements were undertaken to determine the effect of the cleaning method on surface chemistry and wettability. After cleaning, the substrates were coated by plasma polymerized octadience, acrylic acid or allylamine thin films. The surface chemistries and film thicknesses of the plasma polymerised films were determined by XPS and variable angle spectroscopy ellipsometry respectively. The plasma polymerised films were immersed in both Milli-Q water and phosphate bufferedsaline for time periods of 1, 24 and 168 hours. Films were again analysed via XPS and ellipsometry to

Page 25 VASSCAA-9 - The 9th Vacuum and Surface Science Conference of Asia … / Book of Abstracts

determine the influence of substrate cleaning, immersion solution and immersion duration onfilm stability. Substrate cleaning was shown to have an influence on film stability with visible pitting on some films, even after only 1 hour of immersion. Substrate cleaning is an important steppriorto the deposition of thin films and can be used to extend the solution stability of plasma polymerised films, which has important implications for a variety of biomedical applications.

Summary:

Speaker Sessions and Seminars / 50

Mild plasma configuration yielding efficient doping on graphene surface

Goo-Hwan Jeong1

1 Kangwon National University

Corresponding Author(s): [email protected]

In this talk, I will present the effectiveness of a mild plasma configuration in order to dope nitrogen on graphene without defect formation. The system is a vertical-type direct-current plasma with parallel electrodes. We change the electrode configuration and adjust the plasma input power and treatment time to utilize various ion-bombardment energies and plasma doses. The up-cathode system with a powered upper electrode and ground lower anode is more suitable than the traditional down- cathode system for efficient plasma doping. This configuration yields a low-energy ion processand thus suppresses high-energy ion-induced damages. The graphene was prepared by mechanical exfoliation and the doping was performed using ammonia gas. The degree of a structural damage on graphene after the doping was mainly evaluated using Raman spectroscopy. Finally, the structural evolution of graphene and the doping components with respect to the plasma conditions are extensively characterized with Raman spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. The results provide an effective doping condition for doping nanomaterials without plasma-induced damage.

Summary:

Speaker Sessions and Seminars / 257

Functional surfaces and devices enabled by two-dimensional materials

Baohua Jia1

1 Swinburne University of Technology

Corresponding Author(s): [email protected]

Two-dimensional (2D) materials and their derivatives have attracted unprecedented enthusiasm during the past decade due to their exceptional mechanical, thermal, optical, and electrical properties not available in conventional materials. This article explores the innovative surfaces of 2D materials, which enable diverse applications of 2D materials by using the one-step mask-free direct laser printing (DLP) method [1]. Our results have demonstrated the great potentials of two-dimensional material films as an emerging integratable platform for ultrathin, light-weight and flexible photonic, electronic and biological devices towards all-optical communication, microscopic imaging, energy storage and biological applications [2-4]. Reference: [1] H Lin, B Jia, M Gu, Optics letters 36 (3), 406-408 (2011).

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[2] X. Zheng, B. Jia, X. Chen, M. Gu, Adv. Mater 26, 2699 (2014). [3] S. Fraser, X. Zheng, L. Qiu, D. Li, B. Jia, Applied Physics Letters, 107, 031112 (2015). [4] X. Zheng, B. Jia, H. Lin, L. Qiu, D. Li, M. Gu, Nature Communications, 6, 8433 (2015).

Summary:

Speaker Sessions and Seminars / 63

The role of lattice dynamics in the superconductivity enhancement at FeSe/SrTiO3 interface

Guo Jiandong1

1 Institute of Physics, Chinese Academy of Sciences

Corresponding Author(s): [email protected]

The superconducting transition temperature (TC) of monolayer FeSe on SrTiO3 is significantly enhanced to 60-70 K in comparison with the bulk TC of 8 K. To understand the mechanism of the extraordinary interfacial phenomenon, extensive investigations have been carried out with complementary surface analyses techniques. We use the high-resolution electron energy loss spectroscopy (HREELS) to study the system from the perspective of lattice dynamics. Recently we have developed a new strategy for HREELS, which can simultaneously measure the energy and momentum of surface elemental excitations with high energy and angular resolution, as well as detecting efficiency and sampling density. By growing epitaxial FeSe films on SrTiO3, we study the phonon behaviors of FeSe. Although the superconductivity shows dramatic dependence on FeSe film thickness, no change of phonon energy or line width is detected. On the other hand, we detect the Fuchs-Kliewer (F-K) phonon modes of SrTiO3 substrate on FeSe surface. It is revealed that the electric field generated by the F-K phonon can penetrate into FeSe and strongly interact with electrons. With the increase of FeSe thickness, the penetrating field intensity decays exponentially, associated with the superconductivity enhancement weakened. We conclude that the SrTiO3 F-K phonon penetrating into FeSe is essential in the interfacial superconductivity enhancement.

Summary:

Poster Session B / 20

The electrical properties of carbon nanowalls by the depostion of conductive oxide film

Author(s): Sejin Jung1

Co-author(s): Wonseok Choi* 2 ; Seung-Cheol Yoo 2 ; Sangjoon Lee 2 ; So Yeon Lee 2 ; Hyunil Kang 2 ; Jung Hyun Kim 3 ; Jae Hyeon Jeon 4 ; Dong-Gun Lim 5 ; Hyun Suk Hwang 6

1 Department of Electrical Engineering, Hanbat National University, Daejeon 34158, Republic of Korea 2 Department of Electrical Engineering, Hanbat National University 3 Department of Advanced Materials Science and Engineering, Hanbat National University 4 Department of Industrial and Management Engineering, Hanbat National University 5 Department of Electronic Engineering, Transportation National University 6 Department of Electric Engineering, Seoil University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

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To improve the electrical properties of carbon nanowalls(CNW), conductive oxide films such as indium tin oxide(ITO), aluminium-doped zinc oxide(AZO), zinc oxide(ZnO) and gallium doped zinc oxide(GZO) were deposited on the surface of carbon nanowalls. CNW were grown directly on silicon wafers using microwave plasma-enhanced chemical vapor depostion(MPECVD). Conduc- tive oxide films were deposited by rf magnetron sputter on the carbon nanowalls. The imagesof carbon nanowalls deposited with oxide films were identified by field emission scanning electron microscope(FE-SEM), and the components of the specimen were analyzed using an energy dispersive spectrometer(EDS). The Structural properties of the specimen were analyzed using a Raman spectrometer. The crystals were analyzed using x-ray diffraction spectroscopy(XRD). Electrical properties were analyzed using Hall measurements and 4-point probe.

Summary:

Speaker Sessions and Seminars / 29

Entropy-Driven Spontaneous Dissociation of Fluoroacetic Acids in Ice

Heon Kang1 ; Youngwook Park1 ; Sunghwan Shin1

1 Seoul National University

Corresponding Author(s): [email protected]

Ordinary chemical reaction is difficult to occur in ice at low temperature, where atoms and molecules are frozen in position with minimal thermal energy and entropy. Contrary to this general knowledge, fluoroacetic acids dissociate spontaneously in ice, according to studies with reflection absorption infrared spectroscopy and H/D isotopic exchange experiment. Fluoroacetic acids dissociated almost completely to ions in ice (both amorphous solid water and crystalline ice) at 8-140 K, which indicates a significant increase of the acidity as compared to that in aqueous solution at roomtem- perature. Formic acid and acetic acid did not dissociate under the same conditions. The enhanced dissociation of fluoroacetic acids is attributed to the high mobility of excess protons in iceandits entropy-increasing effect.

Summary:

Poster Session - Main Hall Tuesday / 54

Improvement of foreline plasma optical emission spectroscopy for monitoring plasma processes

Dae-Woong Kim1 ; Jin Young Lee1 ; Min Hur1 ; Woo Seok Kang1 ; Jae-Ok Lee1

1 Korea Institute of Machinery and Materials

Corresponding Author(s): [email protected]

Recently, advanced process control (APC) for the semiconductor and display industry becomes important due to tighter process windows. Therefore, process monitoring techniques providing reliable diagnostics data for the APC have attracting considerable attention. The industry-compatible process monitoring techniques are required to satisfy the following conditions: (i) non-invasive to the process, (ii) insensitive against perturbation by the process, (iii) readily comprehensible to process engineer, (iv) applicable regardless of process conditions (power, pressure, gases, etc) and (v) economical as considering of maintenance. In the industry compatible point of view, foreline plasma optical emission spectroscopy (FPOES) technique also referred to as a self-plasma OES or a remote- plasma OES is promising by virtue of its capability to perform in situ non-invasive detection of gas species during processes. Recent applications of the FPOES in monitoring processes are such as the

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end point detection in low-open ratio etch process, the leak and fault detection, the optimization of seasoning, and etc. In this presentation, we show the recent results on improvement of the FPOES. The FPOES is composed of two parts. The first part is electrodes for discharging a plasma in the foreline, thatis independent of the plasma discharged in processing chamber. The second parts is an optical path structure including a window for monitoring the gas species of the plasma using optical emission spectroscopy. For reliable application of the FPOES as a process diagnostics technique, the stability of the plasma in FPOES is important under foreline discharge conditions of pressures and gases. We optimized the electrode structure and the power to obtain the stable plasma in the foreline through comparison experiments using various cylindrical and planar type electrodes. The usefulness of the improved FPOES was tested and validated by applying it to in situ monitoring of real plasma processes. In addition, an active microwave spectroscopy (AMS) measuring the plasma electron density of the FPOES is utilized to improve the FPOES reliability.

Summary:

Poster Session - Main Hall Tuesday / 35

Influence of Metal Assisted Chemical Etching on c-Si Wafer

Author(s): Dong Sik Kim1

Co-author(s): Jeong Eun Park 1 ; Sangmuk Kang 1 ; Hye Kwon Hong 1 ; Young Ho Cho 1 ; Donggun Lim 1 ; Wonseok Choi 2

1 Korea National University of Transportation 2 Department of Electrical Engineering, Hanbat National University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Although there are many factors that degrade solar cell efficiency, this paper primarily focusses on optical losses. The optical losses can be minimized by texturing process that reduces the reflectance by lengthening the path length of the light. For lower cost, as the thickness of the wafer decreases, wet texturing, which consumes a large amount of silicon is difficult to apply to thin wafers. To solve this, the texturing process was carried out by metal catalyst chemical etching(MACE) with a small etching amount. The Ag deposition was carried out using E-beam Evaporator. The process was carried out by first depositing 7 nm Ag on the wafer followed by a 3 minute etching step.During each etching process, the ratio of HF : H2O2 : H2O was varied. We obtained the lowest reflectance of 11.41% under the condition of HF : H2O2 : H2O = 1 : 5 : 10. After optimizing the ratio of the etching solution, Ag was deposited with a thickness of 7 to 13 nm. The deposited wafer was etched for 1 to 5 minutes with HF : H2O2 : H2O = 1 : 5 : 10 solution. As a result, reflectance of 9.37% was observed at etching time of 4 minute and thickness of 7 nm. It was confirmed that thickness of 10 nm exhibited higher reflectance than thickness of 7 nm, and the reflectance was 11.07% at 5minute. The lowest reflectance of 7.41% was obtained in condition of 13 nm and3minute.

Summary:

Poster Session B / 31

Optimization of quantum dots-OLED multistacking EL devices

Jiwan Kim1

1 Kyonggi University

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Corresponding Author(s): [email protected]

Recently, colloidal quantum dots (QDs) have attracted great attention for the next generation display technology. Since the first report of electroluminescence (EL) from QDs in the simple organic materials based structure, the performance of colloidal quantum dot-light-emitting diodes (QLEDs) has been dramatically improved and is now comparable with commercial OLEDs. However, most of QLEDs works has been fulfilled in the form of monochromatic device, while multi-colored QLEDs still remains a long way to go. The OLED technology has many advantages over LCDs (vivid color, no back light unit and high contrast ratio) and the multilayered emission for white lighting is well developed. However, all charge transport layers and emission layer (EML) should be formed using evaporation deposition under high vacuum and the performance of solution based devices for large area displays is not good enough yet. Here, we report the hybrid EL devices combined OLEDs with QDs. After solution-processed deposition of electron transport layer (ETL) and the first EML based on colloidal quantum dots, the second EML based on organic host-dopant system and hole transport layer (HTL) were deposited using thermal evaporation. The inverted structured EL devices with double EMLs were sophisticatedly fabricated to show two EL emissions by matched charge balance. The shift of the color coordinates by increasing the voltage was shown due to change of each peak intensity. The generation of ma- genta color was accomplished by the sequential structure of blue emitting QLEDs and red emitting OLEDs. The unique hybrid EL devices have a great potential to generate a high-quality whitelight with a high color rendering index. The detailed I-V-L characteristics and CIE color coordination were studied to get brighter and more efficient emission.

Summary:

Poster Session - Main Hall Tuesday / 12

Copper indium gallium selenide (CIGS) solar cell devices on steel substrates coated with thick SiO2-based insulating material

Hwa-Jin Lee1 ; JiYeoun Lee2 ; Jongpil Lee2 ; Kyoung-Bo Kim3 ; Moojin Kim2 ; Youngsil Min2

1 The Institute for Industrial Policy Studies 2 Jungwon University 3 Inha Technical College

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

The development of flexible substrates for producing electronic devices, such as solar cells anddis- plays using roll-to-roll processes, has recently attracted considerable interest. Stainless steel (STS) substrates are commonly used in flexible substrates in roll-to-roll processes. STS substrates have many advantages over polymer substrates, such as enhanced chemical stability and lower thermal expansion coefficients. In this study, a solution-based SiO2 material (“sol-SiO2”), which is more adaptable to roll-to-roll processes than dry vacuum coating, was adopted as an insulating diffusion barrier layer and a planarization layer. For the fabrication of copper indium gallium selenide (CIGS) solar cells, the insulating material was deposited on the STS substrates by silk screen printing methods. We prepared and compared three solar cells with different structures: CIGS/Mo/PE-SiO2/MoNa/STS, CIGS/Mo/sol-SiO2/STS, and CIGS/Mo/SLG. The first cell and the second cell have identical substrates. Both structures can be obtained from CIGS/Mo/STS. While depositing CIGS layers, the performance of solar cell devices can deteriorate due to the penetration of Fe atoms in the CIGS films. Therefore, barrier layers such as PE-SiO2 or sol-SiO2 are needed in addition to insulation between the solar cell device and the STS substrate. The device characteristics fabricated by CIGS/Mo/PE-SiO2/STS would be lower than that of CIGS/Mo/sol-SiO2/STS due to Na doping in the CIGS films by sol-SiO2, although the PE-SiO2 film blocked the penetration of Fe. To improve the electrical properties ofsolar devices formed on CIGS/Mo/PE-SiO2/STS structures by the Na doping in CIGS films, a MoNa layer was used between the PE-SiO2 film and the STS substrate. However, the performance of the diodes

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fabricated on these structures was still lower than on CIGS/Mo/sol-SiO2/STS. Next, CIGS/Mo/STS and CIGS/Mo/SLG structures with different substrates are compared. As expected, the solar cell fabricated on CIGS/Mo/STS would show poorer characteristics than that of CIGS/Mo/SLG due to Fe atoms in the CIGS films. To increase cell efficiency, we used a sol-SiO2 layer as an insulating diffusion barrier layer and as a Na doping source layer between the Mo film and metal foil.Asa result, the solar cell devices having the highest efficiency were obtained in CIGS/Mo/sol-SiO2/STS structures. A soluble SiO2-coated insulating film containing oxygen, aluminum, silicon and sodium wasin- vestigated. The addition of insulating layers assisted the decrease in surface roughness oftheSTS substrate. The Ga grading was well preserved in the CIGS films grown on the STS substrates, possibly due to the lower heat capacity compared to the glass substrate. Furthermore, the CIGS films grown on the sol-SiO2 coated STS substrate contained a sufficient amount of Na supplied form the Na-containing sol-SiO2 layer and were free of detrimental Fe impurities. As a result, solar cells with 14 % efficiency were achieved on the SiO2-based layer/STS sample with a Fe atom diffusion barrier and external Na incorporation. This efficiency was higher than the 9.5 % and 12.8 % observed for solar cells on the SiO2/MoNa/STS and SLG, respectively. Therefore, the sol-SiO2 layer is an excellent material for global planarization, diffusion barriers, and for use as a Na supply source.

Summary: A soluble SiO2-coated insulating film containing oxygen, aluminum, silicon and sodium was investigated by EDS and SIMS. XRD, cross-section TEM, and electron diffraction confirmed the amorphous nature of the films. The Rrms obtained from the 3D profiler data were 210 and 157 nm withoutandwith the wet process using the inorganic solution on the steel substrate, respectively. The addition of insulating layers assisted the decrease in surface roughness of the STS substrate. The Ga grading was well preserved in the CIGS films grown on the STS substrates, possibly due to the lower heat capacity compared to the glass substrate. Furthermore, the CIGS films grown on the sol-SiO2 coated STS substrate contained a sufficient amount of Na supplied form the Na-containing sol-SiO2 layer and werefreeof detrimental Fe impurities. As a result, solar cells with 14 % efficiency were achieved on the SiO2-based layer/STS sample with a Fe atom diffusion barrier and external Na incorporation. This efficiency was higher than the 9.5 % and 12.8 % observed for solar cells on the SiO2/MoNa/STS and SLG, respectively. Therefore, the sol-SiO2 layer is an excellent material for global planarization, diffusion barriers, andfor use as a Na supply source.

Poster Session B / 119

Broadband epsilon-near-zero and epsilon-near-pole 1D nanograting metamaterials in near-infrared regime

Tae Young Kim1 ; Minsuk Kim1 ; Wonyoung Kim1 ; Kyu-Tae Lee1 ; Minbaek Lee1 ; Young-Chul Jun2 ; Chang Kwon Hwangbo1

1 Inha University 2 UNIST

Corresponding Author(s): [email protected], [email protected]

Light absorbers have drawn significant attention in a wide variety of research areas, including photovoltaics, sensors, photodetectors, and thermoelectrics. Although various plasmonic and photonic nanostructure configurations have been adopted to demonstrate the light absorption enhancement, a bandwidth of such light absorbers is typically narrow, thus limiting their potential for many applications. In this study, we demonstrate a broadband near-infrared metamaterial absorber, where indium tin oxide (ITO) is selectively deposited on a patterned silicon substrate at a subwavelength scale, based on a combination of epsilon-near-zero (ENZ) and epsilon-near-pole (ENP) resonances. The ENZ resonance that depends primarily on a material is at ENZ wavelength of 1290 nm,whilethe ENP resonance, which is easily tuned by altering a fill factor of a metamaterial structure, is created at a longer wavelength regime to achieve light absorption over a wide wavelength range from about 1620 to 2100 nm. Optical properties of the ITO 1D metamaterial absorber structures are investigated theoretically by using effective medium approximations (EMAs) and numerically by employing the finite-difference time-domain (FDTD) method, which present good agreement with experimental results. The strategy described in this paper may provide design principles and guidelines for diverse

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photonic and optoelectronic devices with broadband absorption characteristics, thereby opening up many potential applications.

Summary:

Speaker Sessions and Seminars / 52

Broadband extraordinary optical transmission in a narrow subwavelength gap of infrared wire-grid-polarizers

Wonyoung Kim1 ; Minsuk Kim1 ; Tae Young Kim1 ; Kyu-Tae Lee1 ; Minbaek Lee1 ; Chang Kwon Hwangbo1

1 Inha University

Corresponding Author(s): [email protected], [email protected]

Wire-gird polarizers (WGPs) have placed central roles in a variety of applications such as imaging system, display, and spectroscopy. However, traditional WGPs show low transmission efficiency in midwave infrared (MWIR) and longwave infrared (LWIR) spectral regions, which is attributed to a large index contrast between air and IR-transmitting substrates such as silicon (Si) and germanium (Ge). In this study, we demonstrate the WGPs, where a metallic film is selectively deposited on aSi nanograting substrate by utilizing oblique angle deposition (OAD), with the capability to reach ~80% transmission efficiency over a broad range of the IR spectrum from 3 μm to 8 μm. It is noticeable that increasing a duty cycle of the nanogratings leads to higher transmission efficiency, which is obvi- ously different from those observed in existing WGPs where an array of the metallic wires isdirectly patterned on a flat substrate. Optical properties of the proposed WGPs are thoroughly explored by studying the field distribution into the WGP structures using a finite-difference time-domain (FDTD) simulation and an admittance diagram employing effective medium approximation with a thin film simulation. A significantly enhanced electric field is formed in a narrow subwavelength gap,which is found to be responsible for achieving the broadband extraordinary optical transmission. The presented approach may open the door to various applications including recognition, remote sensing, and target tracking.

Summary:

Speaker Sessions and Seminars / 112

Iron spin-reorientation transition by dynamic interface alloy formation with Mn

F. KomoriNone ; S. NakashimaNone ; T. MiyamachiNone ; Y. TatetsuNone ; Y. TakahashiNone ; Y. TakagiNone ; Y. GohdaNone ; T. YokoyamaNone

Magnetic thin film heterostructures have been widely studied for fundamental interests in theemer- gence of novel magnetic phenomena as well as their promising practical applications. The heterointerface interaction plays a dominant role in the development of interesting electronic and magnetic properties. The coupling at the heterointerface strongly relies on the interfacial structure onthe atomic scale such as atomic roughness, steps and intermixing, which could degrade electronic and magnetic interactions considerably compared to the theoretically predicted ideally-abrupt interface. However, little comprehensive study that takes overall interfacial factors including electronic hybridization on the atomic scale into account and identifies their individual roles has been conducted so far. We use scanning tunneling microscopy (STM) and x-ray absorption spectroscopy/x-ray magnetic circular dichroism (XAS/XMCD) as complementary tools to study the correlation between the microscopic interface properties and macroscopic magnetic properties of Mn overlayers on an fcc Fe thin film. Successive atomically-resolved in situ STM characterizations of the surface structural and electronic properties during the growth of the Mn overlayer in ultra high vacuum (UHV) give crucial

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information on the dynamical process of the heterointerface formation. Element-specific and quantitative observations of electronic and magnetic properties by in situ XAS/XMCD measurements can be linked with microscopic origins of the heterointerface characteristics. Our fcc Fe thin films are grown on Cu(001) with Mn overlayers in UHV. Magnetic properties ofthe ferromagnetically-coupled top two layers in the fcc Fe film on Cu (001) are quite sensitive tothe local lattice strain even on the atomic scale. Thus, the fcc Fe thin film could highlight theroleof atomic-scale interfacial factors with the Mn overlayers. We find in the XMCD measurements that the Fe layer in Mn/Fe thin film heterostructure exhibits a two-step SRT from out-of-plane to in-plane magnetization with increasing the Mn coverage. The origin of the observed two-step SRT is identified by separately evaluating the roles of entangled interfacial factors using STM with atomic-resolution imaging and spectroscopic capabilities. At low Mn coverages (< 1 ML), a considerably rough heterointerface due to the formation of the disordered alloy drastically weakens the out-of-plane magnetization of the Fe layer, accordingly triggering the first step of the SRT. In the second-step SRT, the in-plane magnetic anisotropy of Mn/Fe thinfilm heterostructures is gradually enhanced up to ~ 3 ML Mn coverage. At the same time, an ordered FeMn alloy is formed with the increase of the Mn coverage. With the help of our first-principles calculations, we attribute the stabilization of the in-plane magnetization dominantly to the electronic hybridization of the Fe layer with the ordered alloy at the heterointerface. The present results demonstrate that microscopic characterizations by STM can be effectively integrated into macroscopic ones by XAS/XMCD to achieve a comprehensive understanding the relation between the magnetic properties and the dynamic heterointerface formation. Furthermore, a considerable enhancement of the magnetic anisotropy of the Fe layer across the second-step SRT will provide a new perspective on the materials design using the interfacial alloy to reinforce magnetic thin film heterostructures.

Summary:

Speaker Sessions and Seminars / 21

Reactive sputter deposition of transparent and low refractive-index MgF2 thin films using a double-grid negative-ion retarding electrode

Eiji Kusano1

1 Kanazawa Institute of Technology

Corresponding Author(s): [email protected]

MgF2 thin films deposited by magnetron sputtering show optical absorption in the visible range because of the formation of F defects or Mg clusters by the incidence of energetic F- ions to substrate [1,2]. In addition, deposition rate of sputter deposited MgF2 thin film is less than a few nm/s [1, 2], which is regarded as rather low compared to that of other compound thin films. In this study, effectiveness of negative bias voltage applied to a double-grid electrode set between thecathode and the substrate on increase in film deposition rate and suppression of optical adsorption hasbeen examined in MgF2 reactive sputter deposition using Ar-CF4 mixture as discharge gas. The sputtering apparatus used in the experiments was a batch-type system with the cathodeofa Mg plate (76.2 mm dia., 99.99 % in purity). The distance between the target and the substrate was 51 mm. A double-grid electrode with 120 mm by 120 mm squared was set between the target and the substrate. The distance from the grounded grid to the target and between the two grids were 15 and 6 mm, respectively. The grid adjacent to the target was grounded and the other was biased. The pressure of discharge gas of Ar+CF4 was kept at 0.8 Pa. The flow rates of Ar andCF4 were 2.5 sccm, respectively. The cathode was driven by dc power supply (AE MDX 1.5K). The cathode power ranged 100-108 W for a constant discharge current of 0.3 A. The retarding voltage was changed from 0 to -500 V. Borosilicate glass plates (80 × 80 × 0.9 mm3) were used as substrate. Thickness of thin films was measured by using a stylus profiler. Optical transmittance and reflectance weremeasured by a double-beam spectrophotometer. The change in the retarding voltage affected both the film deposition rate and optical absorption. The MgF2 thin film deposited without applying a retarding voltage to the driven grid showed the multiple-ring-shaped area with ptical absorption. By applying a retarding voltage of -50 V, the ring- shape was disappeared and transparent MgF2 thin films were deposited. The optical absorption

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coefficient of thin films was reduced to <2×10−4 nm−1 in the visible range and the refractive index was <1.40. The film deposition rate was increased to >10 nm/min from < 1nm/min byapplying a retarding voltage of -30 to -500 V. In addition, the film thickness uniformity distribution in the substrate was drastically improved due to the increase of the deposition rate in the area facing to the target erosion. [1] L. Martinů, et al., Thin films prepared by sputtering MgF2 in an rf planar magnetron, Vacuum 35 (1985) 531. [2] K.Iwahori, et al., Optical properties of fluoride thin films deposited by RF magnetron sputtering, Appl. Opt. 45 (2006) 4598 -4602.

Summary:

Speaker Sessions and Seminars / 145

Quinary indium gallium zinc aluminum oxide films and thin-film transistors

Ching-Ting Lee1 ; Hsin-Ying Lee2

1 Yuan Ze University 2 National Cheng Kung University

Corresponding Author(s): [email protected], [email protected]

Recently, thin-film transistors (TFTs) used as switching and driving devices have been widely applied in liquid-crystal displays (LCDs), flexible electronics, smart cards, etc. Several transparent conducting oxide (TCO) films are being investigated to obtain channel layers, owing to their wider energy bandgap and lack of absorption of visible light. In view of their wider energy bandgap, higher transmittance, and reasonably high electron mobility, quaternary indium gallium zinc oxide (IGZO)films have been widely used as the channel layer of TFTs in displays with larger frame size and high pixel resolution. However, IGZO TFTs still face the problem of long-term instability induced by oxygen vacancies in IGZO film. In the previously reports, Al has been incorporated into ZnO-based films to stabilize oxygen and improve their stability, because of its higher bonding energy with oxygen. Consequently, the stability of oxygen in the quinary indium gallium zinc aluminum oxide (IGZAO) films could be improved by the Al-O bonds. Furthermore, the 3s orbital of Al cation can providean extra transport pathway and widen the conduction-band bottom to increase the electron mobility. In this work, high-quality and highly stable IGZAO films were deposited using vapor cooling condensation method to form the channel layer of highly stable TFTs. To investigate the effect of Al, both IGZO and IGZAO films were deposited on sapphire substrates by vapor cooling condensation system. In the system, Al metal and IGZO powder were loaded into respective tungsten boats. During deposition, sublimated IGZO vapor was condensed and deposited on sapphire substrate attached to a stainless-steel holder with liquid nitrogen cooling system. Be- sides, IGZAO films were deposited from IGZO powder heated at 1033oC and Al metal heatedat 1254oC, simultaneously. The channel width (W) and the channel length (L) of the resulting TFTs were 100 um and 10 um, respectively. It was found that the electron mobility and electron concentration of the IGZAO films were 7.2 cm2/V-s and 9.94E15 cm-3, respectively. The maximum iDS of the IGZO and IGZAO TFTswhen operated at gate–source voltage (vGS) of 5 V was 12.1 uA and 20.8 uA, respectively. Compared with the gm of 3.73E-6 S for the IGZO TFTs, the IGZAO TFTs exhibited a better gm of 7.63E-6 S. Conse- quently, the corresponding field-effect mobility uFE of 23.3 cm2/V-s of the IGZAO TFTs was better than that of 11.3 cm2/V-s of the IGZO TFTs. Compared with the S value of 223 mV/dec of the IGZO TFTs, the S value of the IGZAO TFTs was improved to 168 mV/dec. The threshold voltage of the IGZO and IGZAO TFTs changed by 0.51 V and 0.34 V, respectively, as the temperature was changed from 225 K to 300 K. This work was supported from the Ministry of Science and Technology of the Republic ofChina under contract No. MOST 105-2221-E-006-171-MY3.

Summary:

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Poster Session - Main Hall Tuesday / 36

High-temperature Corrosion of Chromium(III) Electroplating in N2/0.1%H2S Gas

DongBok Lee1 ; Xiao Xiao1 ; MinJung KimNone

1 Sungkyunkwan university

Corresponding Author(s): [email protected], [email protected]

The electroplated chromium coatings are emerging as the important candidate material ofchoice for machinery and automobile applications owing to its decorative colour, high hardness, good resistance to wear and corrosion. They are usually synthesized in the hexavalent chromium (Cr+6) bath. However, the hexavalent chromium plating solution suffers from serious health and environmental problems. To alternate the hexavalent chromium plating, the trivalent chromium plating is being developed. It is relatively non-toxic. In this study, chromium(III) coating was electroplated onto a steel substrate, and corroded at high temperatures in N2/H2S-mixed gas in order to study its the corrosion behavior in the serious H2S-containing atmosphere. The electroplated chromium(III) coating was corroded at 500-900 oC in N2/0.1%H2S-mixed gas. Relatively thin Cr2O3 oxide layers formed on the coating, accompanied with the evolution of CO or CO2 gases. The oxidation occurred mainly along the pre-existing cracks in the Cr-C coating. The effect of heating on the microstrure of the Cr-C coating during corrosion tests was also studied. Acknowledgment. This research was supported by Basic Science Research Program through theNa- tional Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B03028792;D.B.Lee)(2016R1A2B1013169;M.J.Kim).

Summary:

Speaker Sessions and Seminars / 143

Performance improvement of perovskite solar cells using novel structure design

Hsin-Ying Lee1 ; Guan-Syun Chen1 ; Yi-Ching Chen2 ; Ching-Ting Lee3

1 National Cheng Kung University 2 Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan, Republic of China 3 Yuan Ze University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

In the past decades, many types of the renewable energy, such as solar power, wind power, and biomass energy, are extensively developed owing to the nature fuel has been gradual decrease. Among these renewable energies, solar power is the most promising. The solar power includes Si-based solar cells, III-V solar cells, organic solar cells, and so on. Among them, the organic solar cells have many advantages including easy fabrication in large area, flexibility, lightness, and low cost. For organic solar cells, perovskite is superior to other organic materials in terms of its small absorption bandgap, small exciton binding energy, long exciton lifetime, and large carrier-diffusion length. Consequently, the perovskite solar cells have attracted much attentions. In this work, multi-layer electron and hole transportation structures were applied to perovskite solar cells to improve the mismatch problem of the carrier mobility. In the perovskite solar cells, the balance electron and hole mobilities reduced the carrier recombination in the cells, which could improve the performance of the cells. The space-charge-limited current (SCLC) method was usedto calculate the electron and hole mobilities of the perovskite devices with various electron transportation layers (ETLs) and hole transportation layer (HTL). Compared with the perovskite devices with PC60BM ETL, the current density and PCE of the perovskite solar cells with PC70BM/C70 dual ETLs and PTB7 HTL treated at temperatures of 100 oC were enhanced from18.22 mA/cm2 to 24.11 mA/cm2 and 7.07 % to 14.11 %, respectively. The performance improvement of the perovskite solar cells with

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PC70BM/C70 dual ETLs and PTB7 HTL treated at temperatures of 100 oC was attributed to that The best carrier mobility balance ratio (μh/μe) of 0.90 for the perovskite devices with PC70BM/C70 dual ETLs and PTB7 HTL treated at temperatures of 100 oC was obtained. This work was supported from the Ministry of Science and Technology of the Republic ofChina under contract No. MOST 105-2221-E-006-149-MY2.

Summary:

Poster Session B / 45

Preparation of GeTe chalcogenide solutions for thin film applications

Eun Kyu Lee1 ; Jeong Min Ahn1 ; Eun Ji Kim1 ; Seung-Yun Lee1

1 Hanbat National University

Corresponding Author(s): [email protected]

Chalcogenide films have been intensively studied due to their versatile applications in thefields of electronic and photonic devices. Many methods of preparing chalcogenide films have been suggested: sputtering, evaporation, chemical vapor deposition, and vapor–liquid–solid growth. While the usual preparation method is to deposit chalcogenide film layers using sputtering, solution-based processes are considered as another promising method due to their simple and cost-effective nature. Spin coating is one of the most well-known solution-based processes, but this solution-based technique available for device fabrication is still rather limited, except for GeSbSe and GeSeTe films. Among chalcogenide materials, GeTe has drawn attention as an active material for the fabrication of phase change memory. It exhibit reversible switching between conductive crystalline and resistive amorphous states when heated and quenched respectively. In addition, Te-rich GeTe alloys have been investigated due to their potential applications in optical waveguides. Thus, we conducted dissolution experiments on bulk GeTe to develop spin-coated GeTe film layers for electronic and photonic applications. Different solvents such as KOH, n-Butylamine, and ammonium hydroxide were used to dissolve GeTe powders. Dissolution kinetics was examined by measuring the weight loss of GeTe powders in solvents. The dissolution rate was significantly different depending onthe kinds of solvents, and agglomerate-free solutions were obtained by varying the weight ratio of GeTe to solvent and magnetic stirring time.

Summary:

Speaker Sessions and Seminars / 7

Surface hardness of flexible carbon fiber sheets enhanced by deposition of organosilicon oxynitride thin films with an atmospheric pressure plasma jet

Yung-Sen Lin1 ; Yi-Chen Lai1 ; Jui-Hung Chen2

1 Department of Chemical Engineering, Feng Chia University 2 1Department of Chemical Engineering, Feng Chia University

Corresponding Author(s): [email protected]

The transparent polymers reinforced by carbon fiber cloth, so-called flexible carbon fibersheets (FCFS), are frequently exploited due to several advantages such as low specific weight, low cost and ease of processing. However, the soft surfaces of FCFS restrain their usage. The constrains ofsoft surfaces for FCFS can be resolved by deposition of hard transparent protective thin films, such as SiO2 and Al2O3 onto the surfaces of transparent polymers. An enhancement on surface hardness of

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FCFS) substrates by deposition of organosilicon oxynitride (SiOxCyNz) with an atmospheric pressure plasma jet (APPJ) by mixing the tetramethyldisiloxan (TMDSO) vapors with O2 gases, injecting into air plasma jet and sprayed onto FCFS substrates at room temperature (~23℃) and an atmospheric pressure is investigated. Surface hardness of the FCFS substrate is improved form 2B for as-received FCFS substrate to 8H for FCFS/APPJ-synthesized SiOxCyNz while tested by the pencil test method (ASTM3363). The nanograins, and the chemical bonds Si-(O)4 and (R)-Si-(O)3 produced inAPPJ- synthesized SiOxCyNz thin films results in a high surface hardness of up to 8H against thepencil 8H scratched under a loading of 765 g at an angle of 45o.

Summary: The nanograins, and the chemical bonds Si-(O)4 and (R)-Si-(O)3 produced in SiOxCyNz thin films byde- position onto flexible carbon fiber sheets (FCFS) with an atmospheric pressure plasma jet (APPJ) atroom temperature and atmospheric pressure results in a high surface hardness of up to 8H for FCFS/APPJ- synthesized SiOxCyNz films, while possess no scratches against the pencil 8H under a loading of765g at an angle of 45o.

Speaker Sessions and Seminars / 53

Surface-confined polymerisation: synthetic chemistry without a beaker

Josh Lipton-Duffin1 ; Jennifer MacLeod2

1 Queensland University of Technology 2 QUT

Corresponding Author(s): [email protected], [email protected]

One of the most intriguing ideas of the last decade is the concept of translating well-known chemical synthesis methods into the realm of surface science. The ability to interrogate individual atoms and molecules by scanning probe microscopies affords new insights into well-established reaction pathways, and in some cases can reveal unexpected and often surprising new structures. Synthesis of polymers via on-surface arene coupling is an intriguing and facile route towards novel 1D and 2D materials. Ullmann coupling has been the most studied of these methodologies, as it offers a convenient and simple way to control the growth of the polymer products by employing the substrate both as the catalyst for initiating the coupling reaction, as well as a template for supporting the product and driving its growth into well-ordered domains.[1] In this seminar I will describe our longstanding interest in molecular reactions with the aim of producing new interesting and functional materials, such as simple polyphenylenes,[1] industrially- relevant thiophenes,[2,3] and exotic two-dimensional analogues of graphene. [4,5] I will briefly touch on strategies to avoid the chief perceived drawback of Ullmann coupling: that it is not considered to be a ‘clean’ reaction because most surfaces host both the polymer product and the halogen byproducts, the latter of which block catalytic sites on the surface and ultimately act tolimitthe yield of the product. References [1] J. Lipton-Duffin, O. Ivasenko, D.F. Perepichka and F. Rosei. Small 5, 592 (2009) [2] J. Lipton-Duffin, J. Miwa, M. Kondratenko, F. Cicoira, B. G. Sumpter, V. Meunier, D.F. Perepichka, F. Rosei, Proc. Nat. Acad. Sci 107, 11200 (2010) [3] I. Di Bernardo, P. Hines, M. Abyazisani, N., J. MacLeod, J. Lipton-Duffin, Chem. Commun. 54, 3723 (2018) [4] R. Gutzler, L. Cardenas, J. Lipton-Duffin, M. El Garah, L. E. Dinca, C. E. Szakacs, C. Fu,M.Gal- lagher, M. Vondráček, M. Rybachuk, D. F. Perepichka, F. Rosei Nanoscale 6, 2660 (2014) [5] L. Cardenas, R. Gutzler, J. Lipton-Duffin, C. Fu, J. L. Brusso, L. E. Dinca, M. Vondráček, Y.Fagot- Revurat, D. Malterre, F. Rosei, D. F. Perepichka, Chem. Sci., 3, 3263 (2013)

Summary:

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Speaker Sessions and Seminars / 18

Molecular nanoarchitectures from on-surface reactions and assembly

Jennifer MacLeod1

1 Queensland University of Technology (QUT)

Corresponding Author(s): [email protected]

One of the goals of nanoscience is achieving precise control over the structure and function of nanoscale architectures at surfaces. Bottom-up approaches using molecular building blocks present a flexible and intuitive approach to this challenge. Combining the Lego-like modularity of molecules with the epitaxial and reactive influences of surfaces creates a range of opportunities to build exciting new nanoarchitectures. Reacting molecules on a surface can allow for the fabrication of extended covalent nanostructures with enforced planarity. I will discuss our recent work in studying C-C coupling reactions of halo- genated and carboxylated molecules at metal surfaces, where we have been focussing on understanding the effect of heteroatoms in the reaction process and the subsequent formation of oligomeric and polymeric structures, using a combination of scanning tunnelling microscopy, photoelectron spectroscopy and near-edge x-ray absorption fine structure to gain a well-rounded insight into the process.

Summary:

Poster Session - Main Hall Tuesday / 13

Environmental XPS characterization of a bioengineered gold nanoparticle/porous silicon interface with calibrated surface conductivity

Chloe Rodriguez1 ; Vicente Torres Costa1 ; Oscar Ahumada2 ; Cebrián Virginia2 ; Cristina Gomez Abad2 ; Ana Díaz2 ; Miguel Manso Silvan1

1 Universidad Autónoma de Madrid 2 MecWins

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Porous Silicon (PSi) platforms are attractive supports for biomedical devices in a wide range ofthera- peutic and diagnostic applications. PSi structures are in fact biodegradable and can be easily biocon- jugated. It is the association of a tailorable pore structure and a precise conjugation that provide the final properties of a PSi based biomedical assembly. In the present work, we have merged thecon- jugation strategies of PSi surfaces with those of gold nanoparticles (GNPs). From the side of PSi, an immunosensitve interface was formed by modification of the PSi surface with (3-Glycidyloxypropyl)- trimethoxysilane (GPTMS) and anchorage of an antibody (against prostate specific antigen (PSA), a cancer biomarker). The same antibody was tethered to GNPs so that calibrated interaction between platform and particles could be achieved by performing a sandwich assay with different concentrations of PSA. The process of surface modification of PSi was monitored step by step byusing environmental X-ray photoelectron spectroscopy (env-XPS). This analysis showed that the freshly formed PSi presented no C-H contamination, the C-O contribution was the determinant contribution after GPTMS activation and that the O-C=O peak presented an intensity much more in agreement with what expected for a typical aminoacid chain than what typically reported with conventional XPS. The env-XPS analysis further confirmed the presence of GNPs on the surface. By performing identical protocols on PSi supports with interdigitated NiCr electrodes we could probe the surface conductivity. The NiCr contact formation implied an ion beam creation of 200 nm deep slotsand their filling with NiCr, deposited by magnetron sputtering. The changes in the impedance upon PSA binding at different concentrations were detected. Relevantly, a device equivalent circuit could

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be proposed containing a series resistance element related to the surface conductivity. The series resistance decreased (the surface conductivity increased) for increasing concentrations of PSA. A combined dark-field and scanning electron microscopy study of the PSi surface after the bioassay demonstrated the increasing density of GNPs at higher PSA concentrations. The results suggest that specific immune reactions can be exploited to biofabricate interfaces with controlled physical parameters such as surface conductivity, which can be reversely used to fabricate highly sensitive biosensor devices.

Summary:

Speaker Sessions and Seminars / 60

X-ray photoelectron spectroscopy as a tool for control superlattice heterostructures quality and surface bilayer formation

Leszek Markowski1

1 Institute of Experimental Physics, University of Wroclaw, Poland

Corresponding Author(s): [email protected]

X-ray Photoelectron Spectroscopy (XPS) is probably the most widely used surface analysis technique. Using it, it is possible not only to determine the chemical composition of a given material, but also concentrations of all elements forming it. Additionally, XPS is very useful to ascertain the thickness of adlayer deposited on any kind of solid state substrate. The depth from which the information arise is typically not larger than 10 nm. This makes XPS especially suitable in nanotechnology applications. In this talk it will be shown how, using XPS: - a quality of superlattice heterostructures produced, - progress of a surface bilayer formation (e.g. double layer of graphene on SiC surface or bilayer of Ga on GaN), - thickness of the deposited adlayer when a surface bilayer is formed (e.g. during thermal treatment) on superlattice substrate, can be determined. The given formula can be easily extended to more complicated compounds which makes themvery useful in practical applications.

Summary:

Speaker Sessions and Seminars / 69

On-surface bottom-up synthesis of azine derivatives displaying strong acceptor behavior nerea ruiz del arbolNone ; irene palacioNone ; gonzalo Otero-IruruetaNone ; jose ignacio MartínezNone ; pedro de andresNone ; O. Stetsovych3None ; M MoroNone ; P MutomboNone ; martin svecNone ; Pavel JelinekNone ; luca FloreanoNone ; gary ellisNone ; maria francisca lopezNone ; jose a. martin-GagoNone

Organic heterostructures based on acceptor-donor molecules on surfaces have become strategic materials due to their huge technological impact in fields such as organic light-emitting diodes (OLEDs), organic field effect transistors (OFETs), or solar cell devices, amongst others. In particular, thecharge transfer process promoted by donor/acceptor molecules at the interface with metal electrodes may induce a realignment of the energy levels that can be exploited to tune the transport properties of the system [1]. In the present work, we use on-surface chemistry to synthesize a strong electron acceptor organic molecule directly on a Cu(110) surface [2]. By a thermal annealing process, p-aminophenol (p-Ap) molecules deposited on Cu(110) undergo an azine-coupling reaction. Both, the chemical reaction

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mechanism and the charge transfer process induced by the substrate were followed by complementary surface techniques (nc-AFM/STM, XPS, NEXAFS and LEED) as well as by theoretical calculations (Fig.1). We observe that Cu(110) catalyzes a chemical reaction between two p-Ap molecules giving rise to a quinoneazine (QAz) molecule. The resulting molecule accepts 1.2e- from the substrate, which brings on a charge redistribution with recovering aromaticity, leading to an azo compound behavior. [1] R. Otero, A. L. Vázquez de Parga, J. M. Gallego, Surf. Sci. Rep. 2017, 72, 105–145. [2] N. Ruiz del Arbol, I. Palacio, G. Otero-Irurueta, J. I. Martínez, P. de Andrés, O.Stetsovych, M. Moro, P. Mutombo, M. Svec, P. Jelinek, L. Floreano, G. J. Ellis, M. F. López, J.A. Martín-Gago. Andgewvante chimie, in press.

Summary:

Plenary / 126

Electron Accumulation at Semiconducting Surfaces

Chris McConville1

1 RMIT University

Corresponding Author(s): [email protected]

The phenomenon of electron accumulation has been observed and identified at the surfaces ofnu- merous semiconducting materials, including ZnO and InAs, and is in marked contrast to the electron depletion typically observed at the surfaces of conventional III-V, II-VI and Group IV semiconductor materials. However, with the advent of high-quality epitaxially grown materials, a more general model of surface electron accumulation has been developed – particularly following the discovery of this phenomenon at the surfaces of the Group-III nitride material, indium nitride (InN). More recently still, electron accumulation has been observed at the surfaces of a particular sub-set of epitaxial oxide semiconductor materials, that display both optical transparency and a high degree of electrical conductivity, the so-called transparent conducting oxides (TCOs). In this presentation examples from the surface and bulk electronic properties of InN, In-rich InGaN, and several epitaxially grown oxide semiconductors, including In2O3, CdO and ZnO, will be discussed along with the effects of modifying their surfaces by controlled adsorption. The valence band density of states and the surface electronic properties of these materials have been studied using high-resolution synchrotron radiation angle-resolved photoemission (SR-ARPES) and core-level photoemission spectroscopy with hard x-rays (HAXPES), and these data are compared with theoretical DFT band structure calculations. The origins of the phenomenon of surface electron accumulation and the quantized natureof the surface 2D electron gas, will be discussed in terms of the band structure and intrinsic properties of these materials.

Summary:

Speaker Sessions and Seminars / 56

Hierarchical biomimetic porous tantalum fabricated by liquid metal dealloying for biomedical applications

Author(s): Sanka Mendis1

Co-author(s): Wei Xu 2 ; Daniel Liang 3 ; Ma Qian 4

1 RMIT University/CSIRO 2 Macquarie University 3 CSIRO

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4 RMIT University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

Robust biological activity and rapid osseointegration plays an important role in implant stability and fixation in order to deliver better surgical outcomes for patients. Hence, closely mimicking the topological features of natural human bone can lead to greater osseointegration at the bone- implant interface. Here, we have introduced a selective corrosion based method to synthesise a multi-scale open porous surface coatings via liquid metal dealloying and microstructure control. Liquid metal dealloying offers a versatile method to rapidly produce unique hierarchical surface coatings with tuneable porosity, ligament structure and layer thickness. This is demonstrated by creating a number of open porous Ta coatings with nano-to-micro scale microstructural characteristics by dealloying in liquid Bismuth melt. The effect of precursor microstructure, composition and processing conditions on the ligament structure and coating thickness were discussed in detail. The resultant porous structure due to the careful control of the precursor composition and microstructures presents a hierarchical morphology with bimodal pore distribution, which results in a higher porosity and surface-area-to-volume ratios. The porous coatings achieved in this work consists of bimodal porosity with interconnected nano-porosity within the range of 70-500 nm and micro-scale porosity, ranging from 1-10 m, which is driven by precursor microstructure control. The effect of temperature, immersion time and grain-boundaries, and its effect on dissolution, ligament coarsen- ing and stability of the coatings are also discussed in detail. Overall, the liquid metal dealloying process provides a rapid fabrication process for designing multi-scale hierarchical porous structures with tuneable functionality.

Summary:

Speaker Sessions and Seminars / 64

Hidden complex magnetic interaction at La0.67Sr0.33O3/SrTiO3:Nb (111) interface

Meng Meng1

1 Institute of Physics, Chinese Academy of Sciences

Corresponding Author(s): [email protected]

One of the major goals in condensed matter physics is to search for materials with multifunction- ality at the quantum level. Strongly correlated oxides seem to be one of the most attractive candidates due to the collective behaviors emerged from strong interactions and correlations among their degrees of freedoms. Incorporating strongly correlated oxides into epitaxial heterostructures expands the space of new phenomena possible due to dimensional confinement and interfacial coupling. La0.67Sr0.33MnO3 (LSMO) is a key example of a strongly correlated perovskite oxide material in which a subtle balance of competing interactions gives rise to a ferromagnetic metallic ground state. This balance, however, can be easily tuned at interfaces. By constructing a strong polarinter- face between [111]-oriented LSMO and SrTiO3:Nb, the electronic and structural symmetry mismatch leads to lattice and charge modification which changes the magnetic interaction at the interface. An antiferromagnetic interaction stabilized at the interface results in spontaneous magnetic moment reversal and inverted hysteresis effects, which demonstrate that intimate competition in electronic, spin and lattice degrees of freedom in transition metal oxides can lead to new functionality.

Summary:

Speaker Sessions and Seminars / 15

Low-pressure/environmental electron and photoelectron techniques; a new age for a merged biointerface analysis.

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Manso Silvan Miguel1

1 Universidad Autónoma de Madrid

Corresponding Author(s): [email protected]

Surface and interface bio-analytical systems can be categorized, as well as surface modification and biofunctionalization processes, into wet and gas phase (mostly vacuum) operating techniques. While wet and gas phase biofunctionalization routes have coexisted and are even used in sequential processes, the use of traditional vacuum analytical techniques has been severely criticized due to modification of natural thermodynamic conditions and potential sample damage. This has notfullyex- cluded the use of electron microscopies (EMs) and photoelectron spectroscopy (XPS) in the analysis of biointerfaces, but has created controversies by comparison with information provided by wet analytical processes. That is the reason why, many biointerface analysis studies using mechanical, electrochemical or optical transduction of biomolecular sorption do not provide additional EM or XPS evidence of the interface. The advantage of some of these techniques (such as the Quartz crystal microbalance or surface plasmon resonance) is the possibility to monitor the kinetics of modification of the biointerface. Nevertheless, these techniques monitor exclusively the addition of new matter (as added mass or added index of refraction) and leave a margin of uncertainty (depending on the considered protocol) on the matter actually adsorbed on the surface. New technological advances, mainly electron selective pinholes enabling pressure gradients, have allowed the development of so called environmental electron microscopies (envEM) and environmental photoelectron spectro- scopies (envXPS). These new advancements demonstrate that, even if analyses do not takeplace at atmospheric conditions, the analyzed biological samples keep a hydration layer as the most significant physicochemical trace of their pristine state upon analysis. The control of thermodynamic conditions in envEMs (particular case of a wet scanning transmission EM) allows for instance a recording of water adsorption isotherms from the contrast change induced by a water adsorption progressing at increasing relative humidity. In the case of envXPS, the presence of a water layer is evidenced by a trace component in the O1s core level, assigned to water in the vapor phase. From these seeding fundamental results, we provide several examples of how envEMs and envXPS have already complemented applied biointerface structures in the therapeutic and diagnostics field. These studies suggest that the gap to make compatible the results of the analysis of biointerfaces by wet and vacuum techniques is shortening and may open a new age for a fully merged biointerface analysis.

Summary:

Speaker Sessions and Seminars / 251

Nanoscience as a discipline and its impact on modern society

Author(s): Ana G Silva1

Co-author(s): Christian Teichert 2 ; Lars Montelius 3 ; Sidney Cohen 4

1 Universidade Nova de Lisboa 2 Montanuniversitaet, Leoben, Austria 3 International Iberian Nanotechnology Laboratory 4 Weizmann Institute of Science, Israel

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

IUVSTA Nanometer Structures Division Highlights Nanoscience as a discipline and its impact on modern society Corresponding author: Ana G. Silva, [email protected] In the highlight seminar of scientific Nanometer Structures Division (NSD) of IUVSTA we provide an overview of some recent developments in nanoscience and how its applications comprise a vital contribution to social well-being, contributing to a sustainable economy. Nanoscience impacts on

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a variety of technologies such as energy, nano-electronics, communication, health, smart cities and the environment. Examples are given in a range of areas. New materials have mushroomed since development of nanomaterials – here we novel synthetic techniques, such as preparation of core-shell nanoparticles which are used to tune photocatalytic activity; formation of nano-columnar Ti displaying both antibacterial and black metal material properties; preparation of chalcopyrite nanowires, which can be applied in photovoltaics with high conversion efficiency’; growth of PdO-coated WO3 nano-needles showing extreme sensitivity and selectivity to hydrogen, and finally use of laser abla- tion to form nanoparticles, nanowires, and nanostructured materials. Nano-tools are also opening new opportunities. We present a reproducible method for depositing 1-2 nm passivation layers, with atomically sharp interfaces, for SiC nano-electronics devices. We present in addition, the use of atomic force microscopy to investigate enhancement of oil recovery in reservoirs, as well as to investigate wetting properties of unique WS2 nanotubes to elucidate their incorporation in biopoly- mers. Additional examples include controlled manipulation of single molecules by the AFM tip, a video-rate AFM to examine dynamics of biological systems, and controlled manipulation of organic semiconductor crystallites on 2D materials by the atomic force microscopy (AFM) tip. The seminar will include recent and significant achievements of the members of the Nanometer structures scientific division and their colleagues. Acknowledgments Ana G. Silva, Chair of the Nanometer Structures Division (NSD) of IUVSTA, acknowledges Lars Montelius, President of IUVSTA, for his most valuable support by presenting the seminar on NSD behalf. Ana G. Silva acknowledges, Christian Teichert and Sidney Cohen, respectively vice-chair and scientific secretary of NSD division for their exceptional support. In addition, Ana G. Silva acknowledge the contributions of the members of the division and their colleagues who kindly share their most recent research developments. The highlights seminar includes contributions from Nancy A. Burnham, Carla Bittencourt, José Garcia-Martin, Yves Huttel, Nikolay Nedyalkov, Sasha Sadewasser, Takayuki Uchihashi, Christian Teichert, Sidney Cohen and Ana G. Silva.

Summary: IUVSTA Nanometer Structures Division Highlights

Plenary / 256

Connected Science for Society: A Key Enabler for Disruptive In- novations

Lars Montelius1

1 International Iberian Nanotechnology Laboratory

Corresponding Author(s): [email protected]

Advances in Nanotechnology and Advanced Materials have played a profound role for the last few decades development of the modern society and it has paved the way for the present Digitalization age. Further developments in combination with AI, VR, Big data and Quantum Computation, will in the next decade be a major driver for disruptive innovations in various verticals as well as an effective tool for fostering the meaningful utilization of knowledge for a meaningful and sustainable global development. The digital economy is transforming the science and innovation landscape allowing participatory rapid diffusion of knowledge, competencies and capabilities paving the way for effective andmean- ingful deployment of knowledge. The explosion of IoT-products, massive data and sharing economy services are mega-trends of today´s society and the immense interconnectivity change modern society in a pace never before being witnessed. These major societal developments challenge society. And these changes foster disruptive innovations. A key for such changes is the increased and participatory dialogue in society. This trend is clearly seen in the European funding policies becoming more aligned to mission driven perspectives.

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Vacuum Science & Technologies have enabled the emergence of a number Key Enabling Technolo- gies (KETs). These KETs will make solid contributions to the grand challenges of today, suchas sufficient sustainable energy supply on demand, clean water to everyone, novel e-health solutions with impact on the growing ageing population multi-sickness panorama and life-styles diseases etc. Solutions to these challenges demands increased transversal interdisciplinary participation. Not only transversal within the Sciences but also transversal in all kind of societal dimensions including an increased empowered participation of people. There is a need for an increased effort to effectively close the gap between societal needs andscience & technology offers. The basics for science is curiosity - in the past mostly related to understand how things are related or how things work and nowadays more and more related to missions. Finally, in order to fully tap all possibilities offered within the Key Enabling Technologies there isa continued need to put emphasis on transversal funding support schemes. If not, there is a risk that the enabling character of inventions will either disappear or take very long time to diffuse into other verticals, effectively hampering the innovation capital to be fully exploited.

Summary:

Speaker Sessions and Seminars / 92

Wear performance of Electroless Ni-W-P alloy for coating on the Diamond Powder

Author(s): Kyounghoon Moon1 ; Bongyoung Yoo2

Co-author(s): Mann-Ho Cho 3 ; Tae Joo Park 1 ; Hyoungsub Kim 4

1 Department of Materials Science & Chemical Engineering, Hanyang University 2 Department of Materials Science and Engineering, Hanyang University 3 Department of Physics, Yonsei University 4 School of Advanced Materials Science and Engineering, Sungkyunkwan University

Corresponding Author(s): [email protected]

Today, diamond powder is mainly used as cutting tools for wafer manufacturing techniques. Among them, diamond wire saw(DWS) has advantages over conventional slurry wire saw(SWS) in terms of environmentally friendly and fast cutting speed and is currently being applied to manufacturing single crystalline silicon wafer. For the DWS process, metal-coated diamond powder is used. The main reason for coating metal on the diamond surface is to hold the diamond on the wire and prolongs the life of the diamond wire through heat interruption during the cutting process. Electroless deposition method, which is cheap way for uniform coating are mainly used to deposit metal on the surface of the diamond powder. Electroless Ni-P have been widely researched because of their properties such as hardness, wear resistivity and corrosion resistivity. Addition of tungsten in Ni-P electroless deposition can improve these characteristics. In this study, the properties of electroless Ni-W-P thin film on the diamond powder with different parameters (temperature, pH, surfactant etc.) were studied. The surface morphology, structure and composition of the Ni-W-P thin film were examined using field effect scanning electron microscope(FE-SEM) and energy dispersive spectrometer(EDS). The concentration of sodium tungstate was increased from 0 to 0.2M to obtain Ni-W-P films containing various W and P contents which were characterized using X-Ray Diffraction(XRD). Also, the corrosion resistivity was observed using potentiodynamic polarization curve with the 3.5% NaCl solution. Hardness tests for measuring wear resistivity were performed using Nano Test Vantage Platform.

Summary:

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Speaker Sessions and Seminars / 97

Epitaxial growth of graphene and 2D heterostructures on SiC for nanoelectronic applications

Author(s): Nunzio Motta1

Co-author(s): Jonathan Bradford 1 ; Mojtaba Amjadipour 1 ; Josh Lipton-Duffin 1 ; Jennifer MacLeod 2 ; Francesca Iacopi 3

1 Queensland University of Technology 2 QUT 3 University of Technology Sydney

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Future applications of graphene in nanoelectronics will depend critically on the perfect control at the atomic level of its direct growth on semiconducting substrates and on the development of novel approaches to introduce a bandgap while preserving carrier mobility. Thermal decomposition of bulk SiC has proven to be an excellent method to grow transfer-free wafer-scale graphene, with the advantage of being perfectly integrated to the Si microelectronic industry fabrication process. Translating this to SiC/Si substrates is a promising but challenging route to decrease the costs. In this work we present results on two processes that are expected to lead to semiconducting 2D nanostructures based on graphene. In the first process narrow SiC mesas, fabricated by patterning SiC/Si substrates using FocusedIon Beam (FIB) are annealed at 1250˚C in UHV. Synchrotron radiation spectroscopy and Scanning Tun- nelling Microscopy confirm the presence of free standing graphene on the nanostructures afterhy- drogen intercalation at 600˚C [1]. In the second process lateral graphene/h-BN heterostructures are grown by topological conversion of epitaxial graphene on bulk SiC, allowing the realization of semiconducting hybrid atomic layers with tunable properties. Boron and Nitrogen replace Carbon upon heated exposure of graphene to ammonia (NH3) and boric acid (H3BO3) vapors: the concentration of h-BN can be controlled via the reaction time. The substitution of h-BN domains in the epitaxial graphene layer is confirmed by x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), while Raman spectroscopy confirms that the reaction starts at defects sites. [1] M.Amjadipour, et al., Nanotechnology, 29,145601 (2018)

Summary: We present results of two processes that are expected to lead to semiconducting 2D nanostructures based on graphene. In the first process we grow graphene by high temperature annealing on narrow SiC mesas obtained by Focused Ion Beam milling. In the second process, lateral graphene/h-BN heterostructures are grown by topological conversion of epitaxial graphene on bulk SiC, allowing the realization of semiconducting hybrid atomic layers with tunable properties.

Poster Session B / 46

Semi-quantitation of VT-XPS spectra of Fe(II) spin-crossover complexes

Outi Mustonen1 ; Alexander R. CrazeNone ; Kyle J. Howard-SmithNone ; Mohan M. BhadbhadeNone ; Feng LiNone ; Christopher MarjoNone

1 Ms

Corresponding Author(s): [email protected]

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The study of spin-crossover (SCO) phenomena between high-spin (HS) and low-spin (LS) statesof octahedral 3d4-3d7 transition-metal ions represents an important area of coordination chemistry. The SCO compounds in this study comprise Fe(II) complexes in an octahedral ligand fieldwitha LS to HS transition triggered by temperature. These complexes have several potential applications, however, design and synthesis of SCO systems with the required properties represents a significant challenge. This investigation sought to identify if the Fe2p splitting could beobserved in situ using variable temperature X-ray photoelectron spectroscopy (VT-XPS) and to test if the spectral changes could be semi-quantified by calibrating to magnetic susceptibility data performed using aSQUID magnetometer. We are also interested in how these XPS spectra differed when the number of Fe(II) metal centres in the complex changed from mononuclear to dinuclear. A dinuclear triple-stranded helicate iron(II) complex that displays a complete spin transition with a gradual-abrupt character at high T1/2 is also reported [1, 2]. The ability of XPS to identify the SCO transition temperature serves as a strong advantage over a bulk measurement technique such as SQUID, as XPS is better suited to measure potential electronic or sensing SCO devices.

Summary:

Poster Session - Main Hall Tuesday / 9

Surface of cavitation-peened Ti-6Al-4V ELI rod for biomedical applications

Author(s): Masaaki Nakai1 Co-author(s): Mitsuo Niinomi 2 ; Kengo Narita 3 ; Osamu Takakuwa 4 ; Hitoshi Soyama 5

1 Kindai University 2 Tohoku Univeristy, Osaka University, Meijyo University, Nagoya University 3 Maruemu Works Co., Ltd. 4 Kyusyu University 5 Tohoku University

Titanium alloys are widely used for biomedical applications because they exhibit both high strength and high biocompatibility, while the wear-related properties are relatively poor. Therefore, the improvement of wear-related properties is desirable for the titanium alloys. For example, fractures of spinal fixation devices, which consist of three components such as rod, screw, and plug, oftenoccur at the contact between the rod and the plug or screw because they are probably caused by fretting fatigue and fretting wear. Therefore, it is preferable to increase the resistance of fretting fatigueand fretting wear on the surfaces of titanium alloys when they are used as a material for spinal fixation devices. In this case, cavitation peening treatment is expected to be a clean and effective surface modification technique; it is performed by high-speed water jet in water and the material surfaces are impacted by collapsing cavitation bubbles, leading to work hardening with introduction of compressive residual stress. Therefore, the cavitation peening treatment was conducted on the surface of spinal rod made of Ti-6Al-4V ELI, which is the most representative titanium alloy for biomedical applications, and the treatment parameters were optimized in order to obtain the peening benefit effectively. The results revealed that the roughness was increased, but the compressive residual stress was introduced successfully on the surface of spinal rod. It indicates that the durability of spinal fixation device made of Ti-6Al-4V ELI is expected to be enhanced by the cavitation peening treatment.

Summary:

Speaker Sessions and Seminars / 58

Simple linear relationship between reactive gas flow rate and discharge power at mode transition on reactive sputter deposition of metal oxides

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Author(s): Takeo Nakano1 Co-author(s): Kei Oya 1 ; Kosuke Kimura 1 ; Masayoshi Nagao 2 ; Hisashi Ohsaki 2

1 Seikei University 2 National Institute of Advanced Industrial Science and Technology (AIST)

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected]

Reactive sputter deposition process has become a very popular method to prepare oxide and other compound films in both academic and industrial fields. In the metal oxide deposition usingthis process, for example, a metal target is sputtered while oxygen gas is introduced into the deposition chamber to form the oxide on the substrate surface. In this process, two distinct operation modes appear corresponding to the target surface condition. In the “metallic mode”, where the sputter etching of the target surface predominates the oxidation, a fast deposition rate is available while the deposited films tend to be off-stoichiometric or rather metallic. In the “oxide mode”, wherethe relationship between the etching and oxidation rate is reversed, stoichiometric films are obtained at the cost of low deposition rate. When applying a constant discharge power, mode transitions are observed by increasing or decreas- ing the O2 gas flow rate; metal to oxide (M2O) transition and oxide to metal (O2M) transition, respectively. In many cases, the transitions occur like state jumps and show a hysteresis. Namely, M2O transition occurs at a higher O2 gas flow rate than O2M one. This phenomenon has been well described by the Berg’s model, in which the gettering of the reactive gases with the deposited metals on the chamber wall plays an important role [1]. Therefore, a cut-and-try approach has been necessary to find the best process parameters because each industrial deposition equipment hasitsown geometric configuration. We have studied the mode transition behavior of Ti-Ar/O2 and V-Ar/O2 systems experimentally, and found a simple linear relationship between the O2 flow rate and discharge power. The discharge was generated by a DC power supply, and the discharge voltage was monitored to detect the mode transition [2]. Two kinds of experimental operations were carried out: one is the constant power operation with changing O2 flow rate, and the other is the constant flow rate operation with changing discharge power. Both were executed at several powers and flow rates, respectively, and the transition points were plotted in XY graph with flow rate and discharge power coordinates. The M2O and O2M transition points, irrespective of the kind of operation, lay on two corresponding straight lines which pass through the origin. It implies that the total mode transition can be predicted by a few pilot experiments. As described, the mode transition is governed by the balance between the etching rate and the oxidation rate of the target surface. Therefore, our result strongly suggests that the target etching rateis proportional to the target power. This could be understood by considering the I-V relationship ofthe magnetron discharge (a kind of abnormal glow discharge) and the incident ion energy dependence of the sputtering yield. In the presentation, the effects of other experimental parameters, e.g. Ar gas pressure and the system pumping speed, will also be discussed.

1. Berg, et al., JVSTA 5 (1987) 202. 2. Depla, et al., JAP 101 (2007) 13301.

Summary:

Speaker Sessions and Seminars / 258

Anti-fouling and Slippery Properties of Lubricant-Infused Sur- faces

Chiara Neto1

1 University of Sydney

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Corresponding Author(s): [email protected]

My group’s research focuses on controlling the nano- and micro-scale structure and chemistry of surfaces to produce advanced functional behaviour. In this talk I will describe a family of bio-inspired surfaces - slippery lubricant-infused porous surfaces - that have the potential to decrease our energy needs by contributing drag-reducing,1 self-cleaning,2 and anti-fouling properties.3 In all cases, our aim is to achieve functional coatings using approaches that are simple to realise and potentially scalable. References: 1. Lee, T.; Charrault, E.; Neto, C., Adv. Colloid Interface Sci. 2014, 210, 21-38. 2. Scarratt, L. R. J.; Hoatson, B. S.; Wood, E. S.; Hawkett, B. S.; Neto, C., ACS Appl. Mater. Interfaces 2016, 8, (10), 6743-6750. 3. Ware, C. S.; Smith-Palmer, T.; Peppou-Chapman, S.; Scarratt, L. R. J.; Humphries, E. M.; Balzer, D.; Neto, C., ACS Appl. Mater. Interfaces 2018, DOI: 10.1021/acsami.7b14736.

Summary:

Speaker Sessions and Seminars / 41

Evaluation of Graded Composite Film Morphology

Author(s): Stanislav Novak1 Co-author(s): Rudolf Hrach 2 ; Martin Svec 1

1 Faculty of Science, J. E. Purkinje University 2 Faculty of Mathematics and Physics, Charles University

Corresponding Author(s): [email protected], [email protected], [email protected]

The paper presents an efficient tool to research morphological properties of various composite structures. It focuses on the composites that are created by metal particles in a dielectric matrix. Nev- ertheless, the results could be used for other similar two-phase systems. The particles are assumed to be more or less randomly distributed in the matrix, and a low metal volume fraction is supposed. The hard-sphere model for generation of the composite structures is described. The Voronoi tessel- lation was chosen as a very efficient method of mathematical morphology. It is able to describe three-dimensional composite structure morphology simply using one two-dimensional section in the given structure. To evaluate the degree of disorder of the structure, a novel scalar measure is introduced. Results for homogeneous and graded composites are presented. It is shown that the scalar measure gives the possibility to precisely evaluate the degree of disorder of the composite structures. The sensitivity of the method is very good and its noise is low. It is independent ofthe section chosen.

Summary:

Speaker Sessions and Seminars / 254

Recent highlights in plasma science and applications

Deborah O’Connell1 ; et al.None

1 University of York

Corresponding Author(s): [email protected]

Plasmas underpin many existing technologies and drive next-generation innovations. Non-equilibrium plasmas are a powerful medium for ionisation, excitation, dissociation, and bond modification, at

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solid surfaces, in liquids and gases. These processes produce an intriguing reactive environment, combining ions, electrons, reactive neutrals and photons. Atom-scale precision can be achieved for etching and deposition profiles enabling advanced manufacturing techniques for a variety of applications from electronic chip manufacturing to solar cell production. Modern trends have seen the advent of plasma medicine applications for cancer treatment and wound healing; micro-chemical reactors can convert waste products or ambient feedstocks into valuable chemicals, or energy storage media for clean energy and agricultural applications. Key to developing these applications for plasma control and understanding the underlying processes are advancing diagnostic and simulation techniques.

Summary:

Speaker Sessions and Seminars / 68

Antimicrobial nanobiomaterials for scaffolds and medical devices

Andrea O’Connor1

1 University of Melbourne

Corresponding Author(s): [email protected]

Tissue engineering and medical implants hold great potential to restore lost tissue functions in the human body. In tissue engineering, biomaterial constructs may play many important roles, including providing space for tissue growth, acting as scaffolding for cell attachment and migration, mimicking native tissue microenvironments and delivering bioactive signals. However, one significant challenge in using biomaterials in the body is the potential for formation of drug-resistant infec- tions and biofilms on implant surfaces, which lead to device failures, multi-billion dollar coststo the health system and adversely affect the lives of millions of patients. Antimicrobial inorganic nanomaterials are an attractive alternative to antibiotic drugs as they can attack microbes viamul- tiple mechanisms, limiting the microbes’ ability to develop resistance. We have thus investigated the potential of selenium nanoparticles as antibacterial biomaterials with much lower cytotoxicity than the commonly used silver nanoparticles. The nanoparticles’ antibacterial properties depend strongly on their size, and an optimal size range exists for low cytotoxicity and strong antibacterial properties. Hydrogel scaffolds with tailored interconnected porous architectures and mechanical properties are produced through combinations of gas foaming and thermally induced phase sepa- ration. Scaffolds decorated by in situ selenium nanoparticle formation from solution impact both Gram-positive (drug sensitive and drug resistant) and Gram-negative bacteria, causing cell damage including membrane permeabilisation. Selenium-based nanomaterials are shown to be promising agents for a range of antibacterial biomaterial applications, including in chitosan scaffolds, which show potential as scaffolds to aid wound healing.

Summary:

Poster Session - Main Hall Tuesday / 8

Corrosion behavior of nickel-titanium alloy with TiO2 layer formed via anodization in HNO3 electrolyte

Author(s): Naofumi Ohtsu1

Co-author(s): Yuma Hirano 1

1 Kitami Institute of Technology

Corresponding Author(s): [email protected]

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Anodization of NiTi alloy using HNO3 electrolyte enables the formation TiO2 layer hardly including Ni over 100 nm in thickness. The TiO2 layer on a metallic surface is expected to play a role ofapro- tective layer against chemical reaction. In the present study, thus, variations of corrosion behavior on NiTi surface derived by forming TiO2 layer via anodization in HNO3 electrolyte with various concentrations was evaluated. The NiTi alloy was chemically polished using a colloidal silica suspension with an average particle size of 40 nm, and thereafter, the ally was anodized in HNO3 solution with the concentration range from 1 to 1000 mM. A substrate and a counter electrode made of Ti were set at a distance of 50 mm, respectively, after which a galvanostatic direct current (DC) was applied for 60 min at aconstant value of 50 mA∙cm-2. The elemental depth profiles and chemical compositions of the anodized surface were analyzed by XPS, and the surface morphologies of the samples were observed using SEM. Moreover, SPM was used for obtaining information regarding the surface topology and potential distribution. Release rate of Ni ion from the surface was evaluated by soaking the samples into a simulated body fluid for 4 h and subsequently determining the Ni concentration in thefluids The HNO3 concentration used affects the layer thickness as well as the pore generation on thesurface. In the range below 100 mM, raising the concentration led to the formation of thicker oxide layer with larger pores. In the range over 100 mM, the thickness turned into decrease due to the dissolution of the oxide layer formed. Unfortunately, the corrosion resistance of the anodized layer was lower than that of an untreated NiTi alloy because of the generation of pores, and concomitantly, Ni release rate from the surface was also accelerated. The rate related with the thickness of layer formed, and the anodic layer fabricated in 100 mM was the thickest and showed the lowest release rate.

Summary:

Poster Session B / 11

Monolithically Integrated Stretchable TFT Array with Liquid Metal Interconnects

Chan Woo Park1 ; Jae Bon Koo1 ; Chi-Sun Hwang1

1 Electronics and Telecommunications Research Institute

Corresponding Author(s): [email protected], [email protected], [email protected]

Although many approaches have been successful in realizing stretchable electronic circuits, it is still required to find out more practical manufacturing schemes that are highly compatible withthe conventional technology. In the present work, we provide a stretchable circuit with an array of oxide thin film transistors (TFTs), where TFTs are located within rigid polyimide islands and connected by eutectic gallium-indium (EGaIn) liquid metal interconnects. By a new “roll-painting and lift-off” technique based on the conventional photolithography, we can produce liquid metal interconnects precisely aligned to preformed TFTs, and obtain monolithically integrated circuits with the hybrid configuration. For constructing stretchable circuits, we first produced oxide TFTs and crossing units of two metal layers within polyimide islands patterned on a Si substrate, and then formed theEGaIn interconnects for connecting those elements, and finally transferred the whole circuit layer toa stretchable polydimethylsiloxane (PDMS) substrate. With this hybrid structure, when the substrate is stretched, only liquid metal interconnects within the PDMS region are elongated accordingly, while solid TFTs within the stiff polyimide region undergo little deformation maintaining stable operations. This scheme is highly compatible with the current flexible circuit technology, asthe liquid interconnects are formed additionally after all other components (including polyimide islands, TFTs, and crossing units) are fabricated on a rigid substrate by conventional processes. For a 4 x 4 array of TFTs within a 20 mm x 20mm area, we demonstrate that the characteristics of each addressed TFT remain nearly constant up to 40% tensile strain.

Summary:

Poster Session - Main Hall Tuesday / 34

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Cu-Assisted Chemical Etching Process for Fabrication of Black Silicon Substrate

Author(s): Jeong Eun ParkNone Co-author(s): Sangmuk Kang 1 ; Hye Kwon Hong 1 ; Young Ho Cho 1 ; Dong Sik Kim 1 ; Donggun Lim* 1

1 Korea National University of Transportation

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Black silicon is surface modification of silicon like nano-structure, that significantly decrease reflectivity of the silicon wafer surfaces. An effective and economical fabrication process forblack silicon is metal-assisted chemical etching(MACE) method which is neither high energy consuming nor complicated process. The MACE method usually involves two steps: metal deposition andchem- ical etching. The copper deposited on the Si wafer surface can attract electrons from the siliconwafer surface and cause the oxidation of Si to SiO2. After the metal deposition, the Si wafer is immersed in etchant. The as-formed SiO2 is etched away by HF and a pit is produced under each particle.In this paper, Cu metal particles were deposited using a solution of Cu(No3)2, HF and DI water. The wafers were then etched by HF and H2O2 solution. To investigate the effects of HF concentration on the surface morphology, the HF concentration was changed from 1.4M to 2M. Through SEM, we observed that large Cu particles were deposited at an HF concentration of 1.4M and showed high reflectance. This is because Cu ion did not uniformly and completely react at a low HF concentration. With an increase of the HF concentration, the size of Cu particles on the surface became smaller and uniform. The reflectance of the textured surfaces ranged from 4% to 3.2% at wavelengths between 400 and 1000 nm. As a result, the lowest reflectance of 3.2% was obtained at concentrations of1.8M and 0.1M for HF and Cu(NO3)2 respectively.

Summary:

Poster Session B / 47

Composition ratio and structural analysis according to Se injection method in heat treatment process after CIGS single target sputtering

Author(s): So Mang Park1 Co-author(s): Jeong Eun Park 1 ; Sang Yong Park 1 ; Jung Hoon Park 1 ; Jackson Bweupe 1 ; Jae Hyeong Lee 2 ; Donggun Lim 1

1 KOREA NATIONAL UNIVERSITY OF TRANSPORTATION 2 SUNGKYUNKWAN UNIVERSITY

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

In this study, after CIGS sputtering using a single target, Se was supplied in various waysduring heat treatment to analyze composition ratio and structural characteristics of the thin film. The thin films were deposited by DC sputtering and heat treatment process during selenization. Thinfilms were analyzed with SEM, EDS, XRD. The pressure was set to 2~6 mTorr as a process variable, the power was set to 60~200 W, and the heat treatment temperature was varied from 150~550 ℃. At a process pressure of 4 mTorr, large crystals and uniform thin films were formed and high deposition rate, high crystallinity and density were observed at 200 W power. After depositing the thin film at 4 mTorr and 200 W, the peak value increased from 550 ℃ when the heat treatment step progressed, showing the preferred orientation. However, to compensate the loss of Se when the heat treatment process preceded, the heat treatment was performed at the same time as the Se supply. As a result, it was confirmed that the composition ratio of Se was increased from 0.81 to 0.86 as shown: Cu=0.91, Ga=0.24 and Se=0.86 from Cu=0.84, Ga=0.22 and Se=0.81. In addition, SEM analysis showed that the grain size became larger and the surface was rough but uniform, and the grain boundaries were

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clearly visible. As a result of XRD analysis, the orientation of the chalcopyrite structure increased in the crystal orientation when Se was supplied and heat treatment was carried out.

Summary:

Speaker Sessions and Seminars / 27

Controlling the photocatalytic activity of TiO2 thin films grown by atomic layer deposition

Mladen Petravic1 ; Ivana Jelovica Badovinac1 ; Iva Saric1 ; Robert Peter1 ; Ivna Kavre Piltaver1

1 University of Rijeka, Department of Physics

Corresponding Author(s): [email protected]

Controlling the photocatalytic activity of TiO2 thin films grown by atomic layer deposition Titanium dioxide (TiO2) represents a perfect example of a multifunctional metal-oxide semiconductor with applications ranging from microelectronics to photo catalysis or medical device materials [1]. Atomic layer deposition (ALD) is widely regarded as one of the most promising techniques for the growth of thin TiO2 films due to its simplicity, reproducibility, the high conformity ofthe obtained films and an excellent control of the layer thickness at the angstrom level[2]. One of the factors that often dictates the properties of ALD films, and therefore their possible applications, is the crystallinity of the final film. While amorphous films of TiO2 are preferable if diffusion barriers are required for a particular application, crystalline films with a specific phaseare often desired for their specific chemical or electrical properties. In addition, the formation ofcrys- tallites in TiO2 films is of great technological interest. For example, TiO2 has been regarded asone of the most promising photo-catalytic materials for environment-protective coatings due to its high photo-catalytic activity, high chemical stability and low toxicity [3]. In the present work, the photocatalytic activities of TiO2 thin films, grown by ALD, were investigated as a function of the grain size and crystal structure. The samples were characterized by scanning electron microscopy, grazing incidence X-ray diffraction, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, atomic force microscopy, and near-edge X-ray absorption fine structure spectroscopy. We show that the crystallinity and the size of crystallites can be controlled over a large range of diameters, from around 70 nm up to 1 μm with five parameters: the type of substrate, the type of Ti precursor, the deposition temperature, the number of ALD cycles (i.e. the film thickness) and the nanometric Al2O3 buffer layers deposited on substrates in the same ALD sequences prior to TiO2 films. The most dramatic increase in size of the plate-like anatase grains, tomorethan1 μm in diameter, was obtained on films grown at 250 oC on Si substrate covered with a 10 nmAl2O3 layer. The photocatalytic activity, determined for each TiO2 film from the degradation of methylene blue under UV irradiation, is more efficient for the anatase phase of TiO2 than for the rutile phase,and increases with the grain size of crystallites. The high photocatalytic activity, combined with thelow processing temperatures used in the present study, open a wide range of applications for different substrates coated with ALD TiO2 films, such as polymers or cellulose-based substrates, ranging from packaging materials for food to water or air purification systems. [1] X. Chen, and S. S. Mao, Chem. Rev. 107, 2891 (2007). [2] M. Knez et al., Adv. Mater. 19, 3425 (2007). [3] J. G. Chen, Surf. Sci. Rep. 30, 1 (1997).

Summary:

Speaker Sessions and Seminars / 177

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Recent Advances in Surface Engineering

Ivan petrov1

1 University of Illinois

Corresponding Author(s): [email protected]

Surface Engineering (SE) is the science and technology of improving the surface properties of materials for protection in demanding contact conditions and aggressive environments. SE also en- compasses engineering new multi-functional surface properties, such as electrical, optical, thermal, chemical, and biochemical properties. It involves multiple or hybrid processes which include substrate modification and deposition of overlayers in complex architectures. These processes enhance adhesion and optimize composition or microstructure to enhance protective properties coupled with other functionality. The substrates may be of complex shapes, like metal-cutting toolsand automotive or aerospace components, and range in size from micrometers, such as in MEMS or NEMS (micro- or nano-electromechanical systems) devices, to meters, such as in architectural glass. The applications are wide-ranging, and include, for example, control of friction, wear-resistance, corrosion-resistance, thermal-barrier coatings, decorative coatings, bioimplants, antimicrobial layers, web-coatings, and thin films with engineered electrical and optical responses. Areas of scientific interest range from first-principle atomistic studies of new materials, which are both hard and ductile, (i.e., tough), to scientific and technological advances in synthesis methods, structural and chemical characterization techniques, property measurements, and performance characterization of surface- engineered parts. I will highlight a few selected SE advances from the past three years.

Summary:

Speaker Sessions and Seminars / 94

The Present Status of Siam Photon Source and Recent Develop- ment of Soft X-ray Beamline

Pat Photongkam1

1 Synchrotron Light Research Institute (Public Organization)

Corresponding Author(s): [email protected]

The Siam Photo Source (SPS), one of two light sources in South East Asia, has been operating for more than 10 years serving academic and industrial users in Thailand, and users from International. The machine is 1.20 GeV second generation light source with storage ring of 8 bending magnets and 3 insertion devices (undulator, multipoles wiggler and superconducting wavelength shifter). The additional superconducting multipoles wiggler will be installed in August 2018 for new beamline called “ASEAN Beamline”. The full energy injection mode has been studied to replace 1.0 GeV injection mode. The beamlines themselves are developed to improve the capability and operating performance. The Soft X-ray beamline is the first beamline installed at SPS. Initially, it was sourced bybending magnet, but later it was upgraded to undulator since 2011. This beamline is for PES, Soft-XAS and PEEM techniques with photon energy range from 40eV and 1040eV. The detail of development will be discussed.

Summary:

Speaker Sessions and Seminars / 77

Diamond Surface Functionalization and Doping for Carbon-based Electronics

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Dongchen Qi1

1 Queensland University of Technology

Corresponding Author(s): [email protected]

Despite being a bona-fide bulk insulator, the surface of diamond presents a versatile platform for exploiting some of the extraordinary physical and chemical properties of diamond, leading to applications such as chemical/biological sensing and the development of high-power and high-frequency field effect transistors (FETs) [1]. On one hand, bare diamond (001) surfaces are reactive, andcan be readily functionalized by organic molecules through chemical reactions such as cycloaddition reaction. Hydrogen-terminated diamond surface, on the other hand, develops an intriguing two- dimensional (2D) p-type surface conductivity when exposed to appropriate surface adsorbate layer such as atmospheric water as a result of the surface transfer doping process. In the first part of the talk, I will describe our recent work in the engineering of diamond surface properties through surface functionalization [2]. The implications of these new diamond surface terminations to potential applications in photochemistry and quantum sensing will be discussed. In the second part of the talk, I will describe our work on the surface transfer doping of diamond by a variety of solid-state acceptors [3]. I will show that by interfacing diamond with suitable materials a 2D hole conducting layer with metallic transport behaviours arises on diamond. Magnetotransport studies at low temperature reveal phase coherent transport in the 2D channel represented in the form of weak localisation and antilocalisation, and are analysed in the context of spin-orbit coupling induced by Rashba effect. We also demonstrate that this surface conducting channel can be exploited to build diamond surface electronic devices such as metal-oxide semiconductor FETs (MOSFETs). Lastly, the prospects for constructing novel quantum devices on diamond surface by making use of this highly tunable 2D conducting layer on diamond are also explored. References:

1. Pakes, C. I., Garrido, J. A., & Kawarada, H. MRS Bulletin, 39, 542-548 (2014). 2. Schenk, A. K., Tadich, A., Sear, M. J., Qi, D.-C., Wee, A. T. S., Stacey, A., & Pakes, C. I. Nanotech- nology, 27, 275201 (2016). 3. Crawford, K. G. et al. Applied Physics Letters, 108, 042103 (2016). 4. Crawford, K. G. et al. Scientific Reports, 8, 3342 (2018).

Summary:

Speaker Sessions and Seminars / 33

Octahedral Engineering and Interfacial Structure of Heteroepi- taxial Complex Oxides

Liang Qiao1

1 University of Electronic Science and Technology of China

Corresponding Author(s): [email protected]

Epitaxial strain, utilizing the lattice-mismatch between heterogeneous systems, has been general- ized as a standard tool to improve or induce unconventional physical and materials properties, such as ferroelectricity and ferromagnetism. The fact it is so successful that it overwhelmingly enveils another important concomitant parameter, the symmetry-mismatch, that naturally occurs at the interface. The latter can be significant based on early theoretical predications, but direct evidence still lacks due to the challenging needs of 1.) characterization techniques, and 2) an appropriate method to separate it from lattice-mismatch. Here we provide experimental evidence that the symmetry- mismatch strongly impact the magnetic and electronic functionalities of complex oxides using epitaxial Cobaltite and Titanate as examples, e.g. suppressing the TiO6 octahedral tilts in CaTiO3 can

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drive it into ferroelectric phase and distortion in CoO6 can induce long range ferromagnetic ordering in thin-film LaCoO3, which is paramagnetic in bulk case. It is also suggested that octahedral engineering may work as a useful tool to tune the functionalities in complex oxide heterostructures.

Summary:

Poster Session - Main Hall Tuesday / 57

Space Resolved Langmuir Probe Characterization of a DC Mag- netron System for Titanium-Aluminum Thin Film Deposition

Author(s): Paz Victoria Ramos1

Co-author(s): Franulfo dela Cruz 1 ; Ivan Culaba 1 ; Christian Lorenz Mahinay 1 ; Juan Gabriel Troncales 1

1 Ateneo de Manila University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

Direct current (DC) magnetron sputtering is a physical vapor deposition (PVD) method that iswidely used in metal thin films deposition for industrial applications. It outperforms other PVD techniques because it is easy to control and is a low-cost option in depositing metal films. The technique uti- lizes magnets which are often used in the magnetron to confine energetic electrons which eventually increases ionization efficiency and effectively improves the deposition rate of the film onto thesub- strate. This paper reports on characterization of the plasma parameters of a DC magnetron glow discharge plasma in an annular magnetron system in argon. The DC magnetron sputtering system is assembled in the laboratory and houses the magnet assembly which is composed of annular magnets and target confined in the cathode. The plasma is produced by a high voltage DC power supply set at V=400-490 volts, working pressure of 1.88x10-2 to 7.5x10-2 torr, argon flow rate of 16-20 sccm and discharge power of 20-23 watts. Space-resolved measurement via cylindrical Langmuir probe is used as diagnostics for the estimation of plasma parameters such as electron temperature, electron density, floating potential, and plasma potential. Ti and Al thin films have been deposited untoSi substrates. Surface properties such as film thickness, hardness and adhesion strength are determined and analyzed with respect to the measured plasma parameters.

Summary:

Speaker Sessions and Seminars / 103

Atmospheric pressure plasmas for the design and tailoring of surfaces and coatings : from fundamental understanding to dedicated surface properties.

François Reniers1

1 Université libre de Bruxelles

Corresponding Author(s): [email protected]

Functional coatings can nowadays be synthesized by atmospheric plasma, which opens interesting possibilities for industrial applications. Antibacterial, anticorrosion, optically active, biocompatible, self-cleaning, superhydrophilic, superhydrophobic, sticky or repellent surfaces can be obtained. However, the still mostly empirical approach used (study of the change in the coating chemistry and properties as a function of the plasma parameters) and the many references to low pressure plasma polymerization theories lead to some limitations in the development of new coatings. In the talk we will present another approach, based on a deeper understanding of the physics and chemistry

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of the plasma itself, and its consequences on the growing film. The drastic effect of the chemistry of precursors and of the choice of the plasmagen gas (argon or helium) on the chemistry, texture and properties of the resulting coatings will be shown. Examples of fluorinated coatings, acrylates, PEG, and ion-exchange membrane films will be described. The plasma phase, or its post-discharge, is studied using atmospheric mass spectrometry (MS), optical emission spectroscopy (OES), and electrical measurements. The obtained coatings were characterized using infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), (dynamic)water contact angle (WCA), atomic force microscopy (AFM), and profilometry.

Summary:

Speaker Sessions and Seminars / 147

Oxide based electronics for neuromorphic computing

Elliman Robert1

1 Australian National University

Corresponding Author(s): [email protected]

In thin film form, transition metal oxides can be subjected to intense electric fields and areknownto exhibit characteristic resistance changes that are of increasing interest for a new generation of low power oxide-electronics, including: resistive random access memory (ReRAM) as a replacement for non-volatile flash memory, field-programmable gate arrays (FPGAs) for reconfigurable electronics, and artificial synapses and neurons for neuromorphic computing. The neuromorphic computing application is particularly interesting as it provides the basis for a compact, low-power neural network capable of repetitive learning tasks, such as image recognition, signal processing or autonomous navigation. Like their biological counterparts, these networks are based on the large scale integration of synapses and neurons, where the former control the amplitude of propagating signals and the latter respond to the relative strengths and timing of these signals. This presentation introduces a new class of solid-state synapses and neurons based on non-volatile resistive-switching and volatile threshold-switching in oxide thin films, respectively. The physical processes underpinning these devices are discussed and examples of device operation are used to highlight their capabilities and limitations.

Summary:

Speaker Sessions and Seminars / 87

Neutron scattering techniques for understanding restricted dimensionality in magnetism: interfaces, surfaces and more!

Kirrily Rule1

1 ANSTO

Corresponding Author(s): [email protected]

In this invited talk I wish to give an overview of neutron scattering at ANSTO. From this we will see neutron scattering as a powerful tool for understanding the structure and dynamics of materials. There are many different types of instruments utilizing neutrons from the OPAL reactor atANSTO and these will be introduced in some detail. In particular I wish to focus on recent scientific results from magnetic materials such as BiFeO3 [1] and linarite [2] and give examples of the information that neutron scattering has revealed. By applying this technique to the study of restricted dimensions, we can devise better ways to develop new materials for future technologies.

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[1] Joel Bertinshaw et al., Nature Communications 7, 12664 (2016) [2] K.C. Rule et al., Physical Review B 95, 024430 (2017)

Summary:

Speaker Sessions and Seminars / 89

Atmospheric-pressure microwave plasma system for cleaning and deposition

L. Bonova1 ; D.K. Patel1 ; A. Farrokhpanah1 ; W. Zhu1 ; N.S. Chopra1 ; David N. Ruzic1

1 University of Illinois at Urbana-Champaign

Current wet chemical processes for cleaning and painting of metal surfaces require multiple steps including cleaning, degreasing, deoxidizing and anodizing/chemical conversion coating to impart the necessary surface modification all while using chemicals with significant environmental andhealth hazards. The most common alternative surface modification methods are laser and plasma-based systems. Plasma systems show promise because a single pass can perform both the surface cleaning and the pretreatment of the metal. The development of a single pass, corrosives-free process for both cleaning and pretreatment of metal surfaces requires a simple but robust process. Atmospheric plasma meets these requirements as it can sequentially clean surfaces, provide surface activation for bond formation, and deposit thin film coatings. The Center for Plasma Material Interaction (CPMI) at University of Illinois has developed novel patented technologies of Evaporative Coatings at Atmosphere Pressure (ECAP). This atmospheric plasma-based system is designed to eliminate chemical waste and remove contaminants using a microwave plasma. The experiments conducted using this system have showed that that it caneffec- tively clean the aluminum surface from heavy oil contamination. Contact angle measurements, XPS and ATR-FTIR techniques were involved to show the cleaning and activation effect of our system. EM field simulations and gas flow modeling were used to predict and set the experimental conditions. With this setup, treatment time under a minute and 400-600 W power is enough to sufficiently clean the aluminum surface. For example, an aluminum sample contaminated with oil layer had a contact angle of 65.02°±0.49°. After a 30 s plasma treatment in Air using 600 W microwave powerand distance of 0.45” from the plasma torch, the contact angle decreased to 8.86°±0.06° indicating the contamination removal while making the surface hydrophilic. A design reiteration of the old system enables an effective coating deposition in addition tothe cleaning and activation processes. This allows for deposition of protective and anticorrosive layers using precursors commonly used in ALD and CVD application. Depositions can also be conducted via Cathodic arc deposition technique (or Arc-PVD) enabled by biasing the target filament with HiPIMS.

Summary:

Poster Session B / 99

Investigation of the Highly Effective Adsorption of Toxic Heavy Metals in Sweat through Multiple Fabric Layers

Author(s): Naoko Sano1 Co-author(s): Tomoko Hashimoto 1

1 Nara Women’s University

Corresponding Author(s): [email protected], [email protected]

Sweat is absorbed into fabric which is worn next to skin such as underwear. Moisture transfer through fabrics have been studied by many researchers to invent more comfortable microclimate

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garments. However, there is no scientific literature reported any behaviour of elements in sweat from the point of surface science during sweat moisture transfers through fabric layers. This work for the first time has attempted to understand the effect on the property of commodity fabricsas multiple layers with the heavy metals with moisture absorption effect. A complete understanding of the mechanism may provide a key to obtaining optimum performance for a particular application. This study shows that heavy metal indeed transfer from the substrate (a wet skin with artificial sweat including a heavy metal) to upper fabric layers and the concentrations of heavy metal ions differing degrees in each layer using laser desorption ionization mass spectrometry (LDI-MS) and secondary electron microscope (SEM). Some combinations of the fabrics indicated highly effective adsorption of heavy metals, more heavy metal ions were observed being preferentially remained on the top layer of particular sets of different fabric assemblies than others. They have no significant correlation with the standard moisture regain. This indicates that specific combinations of different fabric layers enhance molecular absorbency rather than single material layers although each fabric possesses no particular function to absorb purposely. The results may lead a novel invention as adjunctive remedy and/or an additional method for monitoring bioaccumulation of toxic elements in humans.

Summary:

Speaker Sessions and Seminars / 255

Overview of the Neutron Scattering Capabilities at the OPAL Re- search Reactor

Jamies Schulz1

1 ANSTO

Corresponding Author(s): [email protected]

The Australian Centre for Neutron Scattering (ACNS) utilises neutrons from Australia’s multi-purpose research reactor, OPAL, to solve complex research and industrial problems for Australian and international users via merit-based access and user-pays programs. Neutron scattering techniques provide the research community and industry with unique tools to study the structure, dynamics and properties of a range of materials, helping scientists understand why materials have the properties they do, and helping tailor new materials. An overview of the ACNS neutron scattering capabilities at the OPAL reactor will be given together with a selection of scientific and industry case studies.

Summary:

Poster Session - Main Hall Tuesday / 85

The Preparation of Vertically Standing Graphene Sheets onITO Glass and Their Field Emission Properties

Fei ZhouNone ; Haitao ZhouNone ; Chengmin Shen1 ; Hongjun GaoNone

1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences

Corresponding Author(s): [email protected]

The cold cathodes based on the low-dimensional nanoscale materials have exhibited excellent field emission (FE) properties in contrast with the traditional materials. The synthesis control of low- dimensional nanoscale materials, such as morphology, orientation, density, and interval, has become the key technology in higher efficient and size-reducing flat field emission displays. Among them,

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the vertically standing graphene sheets ( VSGs ) are a promising candidates as cold cathode materials applied in FE display devices because they have plenty of high exposed atomic edges, larger aspect ratio, excellent thermal conductivity and good mechanical properties. Here, we reported that the large area and high densities VSGs directly on indium tin oxide (ITO) were prepared at low temperatures by using PECVD method. The morphology, structure and size of the VSGs grown at different temperature were characterized. Furthermore, the field emission properties of VSGs/ITO films at different grown temperature have been compared. The VSGs/ITO film grown at higher temperature (600C) had a larger field-enhancement factor and smaller turn-on field because of more field-emission sites and better electrical conductivity. The results indicatethat the high quality of VSG film and its promising application for large-area field emitters.

Summary:

Speaker Sessions and Seminars / 23

Manipulating the electronic structure and magnetism of spin-orbit Mott insulator by tailoring superlattices

Congcong Fan1 ; Zhengtai Liu1 ; Qi Yao2 ; Dawei Shen3

1 SIMIT, CAS 2 Fudan University 3 SIMT, CAS

In this talk, we will introduce how to fabricate and study the artificial 5d iridate superlattices by the combo of oxide molecular beam epitaxy (OMBE), in-situ angle-resolved photoemission spectroscopy (ARPES) and X-ray magnetic circular dichroism (XMCD) techniques. We successfully fabricated a series of [(SrIrO3)m/(SrTiO3)]n/SrTiO3(100) superlattices using the layer- by-layer OMBE. The high crystalline quality has been confirmed by both Atomically resolved HAADF- STEM and X-ray diffraction measurements. In this series of superlattices, the metal-insulator transition (MIT) is introduced by tuning the thickness of SrIrO3 interlayer. Besides, the emergent interfacial magnetism by such an artificial dimensionality control of iridates is realized. The mechanism of this MIT and the elemental specificity of magnetism have been then investigated by the in-situ ARPES system and the XMCD, respectively. Our results could provide a comprehensive understanding of the phase transition in this spin-orbit Mott insulator.

Summary:

Speaker Sessions and Seminars / 30

Capturing interface processes at the atomic scale by high-speed surface X-ray diffraction

Tetsuroh Shirasawa1 ; Wolfgang Voegeli2 ; Etsuo Arakawa2 ; Takuya Masuda3 ; Toshio Takahashi2 ; Kohei Uosaki3 ; Tadashi Matsushita4

1 National Institute of Advanced Industrial Science and Technology 2 Tokyo Gakugei University 3 National Institute for Materials Science 4 Photon Factory, KEK

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

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Surface X-ray diffraction (SXRD) is one of the most powerful methods that can determine theatomic structure of buried interfaces non-destructively. It is widely used to analyze the structure of solid- liquid and solid-solid interface to understanding the interface processes such as electrochemical reaction and thin film growth. A drawback of SXRD is that the measurements are oftentime- consuming: the data acquisition time is several tens of minutes or more even when a state of the art two-dimensional detector is used, which is in most cases longer than the relaxation time of the structural changes. Capturing the dynamical behavior of interfaces with a sufficient temporal resolution still remains challenging. We have developed a high-speed technique which can acquire a wide range of SXRD profile at once within seconds or less [1]. The method uses an energy-dispersive convergent X-rays, instead ofa conventional monochromatic collimated X-rays. The combination use of the energy-dispersive X- rays and a two-dimensional detector allows the simultaneous acquisition of a SXRD profile without moving the specimen and detector, enabling the real-time monitoring of interface processes [2, 3]. In this talk, we show the capability of the high-speed technique for capturing the atomic-scale processes at buried interfaces: structural change of Pt(111) electrode surface during electrochemical decomposition of methanol, and the atomic-scale growth process of topological insulator Bi2Se3 thin film. References 1. T. Matsushita, T. Takahashi, T. Shirasawa, E. Arakawa, H. Toyokawa, and H. Tajiri, J. Appl. Phys. 110, 102209 (2011). 2. T. Shirasawa, W. Voegeli, E. Arakawa, T. Takahashi, and T. Matsushita, J. Phys. Chem. C 120, 29107 (2016). 3. T. Shirasawa, T. Masuda, W. Voegeli, E. Arakawa, C. Kamezawa, T. Takahashi, K. Uosaki, and T. Matsushita, J. Phys. Chem. C 121, 24726 (2017).

Summary:

Poster Session B / 136

Ferromagnetism of CrO2 under pressure studied using K-edge x- ray magnetic circular dichroism

Anton Stampfl1 ; Nicolas Loh2 ; Richard ClementsNone ; Robert Stamps3 ; Y-C Tseng4 ; Daniel Haskel5

1 Australian Nuclear Science and Technology Organisation 2 ANSTO 3 University of Manitoba 4 Argonne National Laboratory 5 Argonne National Laboratory

Corresponding Author(s): [email protected], [email protected]

Chromium K-edge x-ray magnetic circular dichroism (XMCD) from the half-metallic ferromagnet CrO2 is found to be strongly suppressed by applied hydrostatic pressure such that dichroic signals at 15 GPa are less than half of their ambient values. Band structure and cluster calculations indicate that ~20% of this decrease is due to progressive quenching of the 4p orbital moment as the CrO6 octahedra flatten under pressure. The majority of the XMCD reduction, however, is attributed to loss of magnetisation associated with a rapid lowering of the ferromagnetic ordering temperature, Tc . The decrease in Tc is found to be linear across the pressure range measured with a gradient of –4.74±0.9 K/GPa. Extrapolation of this trend gives a critical pressure for non-magnetism, PC = 45±11 GPa, that is less than the lowest Pc value of 65 GPa predicted by previous band structure calculations. It is argued that stronger antiferromagnetic superexchange interactions, associated with straightening of the Cr-O-Cr bond angle toward 180° under pressure may be responsible for the weakening of ferromagnetism. No change in the x-ray absorption pre-edge is observed as pressure is increased which is consistent with CrO2 remaining half-metallic up to at least 15 GPa.

Summary:

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Poster Session B / 135

High resolution scanning photoelectron microscopy study of l- cysteine and s-benzyl-l-cysteine on platinum: Adhesion mechanisms and radiation damage

Anton Stampfl1 ; S.-C. Wang2 ; M.-L. Huang2 ; Ruth Klauser3

1 Australian Nuclear Science and Technology Organisation 2 National Synchrotron Radiation Research Centre 3 National Synchrotron Radiation Research Center

Corresponding Author(s): [email protected]

Room temperature in-situ deposition of L-cysteine and S-benzyl-L-cysteine on Pt {111} was studied using a high resolution x-ray photoelectron microscope at the synchrotron in Taiwan. Intact cysteine is adhered to the substrate predominantly in its zwitterionic form through the thiol group. More than one layer of cysteine is assembled on the surface. Similarly, benzyl-cysteine formed multi layers on the Pt substrate, with the majority of molecules zwitterionic. Chemisorbed molecules, however, are decomposed in the deposition process, through C-S bond cleavage. Radiation damage to these surfaces from exposure to x-ray radiation is observed. The amino and carboxyl groups appear tobe most sensitive to damage from irradiation.

Summary:

Poster Session B / 133

The adsorption of glycine on alumina: A search for fundamental mechanisms of surface complexation

Anton Stampfl1 ; Julie Murison2 ; Richard ClementsNone

1 Australian Nuclear Science and Technology Organisation 2 ANSTO

Corresponding Author(s): [email protected], [email protected]

Adsorption and surface complexation of biological molecules on inorganic materials are actively studied in such diverse fields as chemistry (geochemistry, biochemistry), biotechnology (medical implants, biosensors, tissue engineering, bioelectronics, biomimetics, artificial photosynthesis), radiation technology (radiation damage and detection), colloid chemistry, surface chemistry and physics, etc. The surface complexation and hence uptake of glycine on Al2O3 from solution was measured, at different pH, and glycine concentrations, by titration. Experimentally derived uptake diagrams (amount adsorbed versus pH) are based on simple surface-complexation models which give the best fit to the titration data. And yet these models are unlikely to be particularly accurate becauseof fundamental assumptions made about surface-proton coordination, stoichiometry, and exchange between surface and solution, and hence surface valency and the simple electrostatic picture used to model the surface-complex-water interface. Whether titration measurements yield particularly quantitative results and whether adsorption is indeed simply driven by proton exchange is not defini- tive. Photoemission spectroscopy provides a way to probe the chemical state of each amino-group: e.g. zwitterions can be observed by the energy shifts of the N 1s and O1slevels. High resolution x-ray photoelectron spectroscopy performed at the Taiwan synchrotron is used to yield a wealth of information about the extent of adsorption at various pH’s, the character of each adsorbate (whether zwitterionic, basic, acidic), and the number of discrete surface sites involved in the adsorption. Titration results show a higher affinity of glycine to alumina at low pH, while valence band photoemission results show the presence of carboxyl groups on the surface and that

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the amine group may be absent. Drying might indeed alter the chemistry of adsorbed species. A number of plausible surface structures are proposed.

Summary:

Poster Session B / 132

The growth of Mn on Cu(100): A core-level photoemission study

Anton Stampfl1 ; Peter Brigden2 ; Richard ClementsNone ; Loh Nicolas2 ; Justin KIng-Lacroix2 ; Hansjoerg Ruppender3 ; Yeukang Hwu4

1 Australian Nuclear Science and Technology Organisation 2 ANSTO 3 Omnivac 4 Academica Sinica, Taipei

Corresponding Author(s): [email protected], [email protected], [email protected]

The deposition of Mn on Cu(100) at a series of coverages from sub-monolayer to approx. 1.5MLis carried out using LEED to monitor the surface structure, and core-level photoemission spectroscopy at a photon energy of 140 eV to examine the changes in the electronic and structural properties of the surface. For each spectrum, a best-fit of component Gaussian-Lorentzian peaks is carried out using an x-ray photoemission spectroscopy (XPS) software package [1] and the relative intensities are used in a simple model to explain how the Mn is incorporated as deposition progresses. Of particular interest in this study is the formation of a c(2x2) surface alloy which is well documented in previous work. A low deposition rate of 0.1 – 0.15 ML/min. is achieved. For low deposition times up to ~2 min. (<0.25ML), the c(2x2) alloy is formed in regions on the surface as observed in STM investigations. In addition to this, the results reported here show that alloying continues for higher coverages together with the additional growth of Mn islands on top of the CuMn alloy, a certain amount of contiguous alloy being built up before any islands form. The formation of Mn islands on-top of the alloy hinders alloy growth. A full alloy monolayer is achieved only with a monolayer of Mn sitting on-top of it. Comparison is made to previous models and STM results on thissystem. The much larger area sampled by photoemission as opposed to that sampled in STM givesabetter overall picture of the surface at any particular coverage. References [1] Neal Fairley, http://www.casaxps.com

Summary:

Poster Session B / 130

The Surface Fermi Surface of Ir{100}

Anton Stampfl1 ; Richard ClementsNone ; Alex Bradshaw2

1 Australian Nuclear Science and Technology Organisation 2 Fritz-Haber-Institut der MPG

Corresponding Author(s): [email protected], [email protected]

The experimental surface band structure for the two phases of Ir{100} was measured at theFermi level using angle resolved photoemission spectroscopy. Electron hole pockets are observed on the

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(1x1) phase centered around the X point, whereas a flat plate-like structure approximately 0.1 eV below the Fermi level is observed on the (hex) phase. Both resonance structures may be related to a high density of states region within the bulk. The disappearance of the band centered around X on the unreconstructed phase has previously been reported for the surface Fermi surface of Pt{100} [1] suggesting similar behaviour. The Fermi surface bands in the late transition metal series ofIr,Pt, and Au may be involved in the mechanism of the very well known surface (hex)-phase reconstruction. [1] A. P. J. Stampfl, R. Martin, P. Gardner, and A. M. Bradshaw, PRB 51(1995)10197

Summary:

Poster Session B / 129

The electronic structure of ZrO2/Si(111)

Anton Stampfl1 ; Richard ClementsNone ; Julie Murison2 ; Gerry Triani2 ; Tun-Wen Pi3

1 Australian Nuclear Science and Technology Organisation 2 ANSTO 3 National Synchrotron Radiation Research Center

Corresponding Author(s): [email protected], [email protected], [email protected]

Zirconium and some of its alloys, oxides and nitrides are known for their anti-corrosive and excellent wear resistant character under a variety of extreme conditions. For example the nuclear industry employs Zr-based materials due to their low neutron absorption character, mechanical strength, toughness, and ability to withstand harsh environmental conditions such as high temperatures and intense radiation. ZrO2 has also been singled-out as a candidate material for inert matrix fuels to be used in Generation IV nuclear reactors. The formation of ZrO2 under different growth conditions leads to variations in electronic properties and crystal structure and hence macroscopic physical properties. Control of growth may enable tuning the electronic and structural properties of this material for specific applications. The current preliminary study investigates the effect of deposition conditions on the electronic and crystal structure of atomic layer deposition grown ZrO2 films on silicon, using synchrotron-based high resolution photoemission, TEM, SIMS, and glancing angle x-ray diffraction. The precursors used in the deposition were ZrCl4 and H2O using two growth temperatures of 200℃ and 300℃. Additionally, ZrO2 films were subjected to rapid thermal annealing at 600℃ to investigate the effect on the valence electronic structure upon crystallization. Results are related to the detailed electronic structure of ZrO2 thin films and bulk material.

Summary:

Poster Session B / 108

The cryogenic and vacuum system for a neutron low-energy bandpass filter spectrometer

Anton Stampfl1 ; Aravinthan Chellappah2 ; Anthony Kafes2 ; Merv Perry2 ; Dan Bartlett2 ; Andrew Eltobaji2 ; Scott Olsen2 ; Frank Darmann2 ; Hansjoerg Ruppender3

1 Australian Nuclear Science and Technology Organisation 2 ANSTO 3 Omnivac

Corresponding Author(s): [email protected]

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Neutron spectroscopy is a powerful technique that involves analysing the inelastically scattered neutron signal from a sample in the thermal and cold neutron energy regime in order to obtain information regarding low energy excitations, vibrational density of states, and phonon distribution, of the material under investigation. Most neutron spectroscopy is performed at large facilities which are either neutron research reactors or neutron spallation sources. Spectrometers generally are medium to large instruments that take can take up considerable space and that involve heavy radiation shielding. In the case of the so-called Beryllium Filter Spectrometer, recently built, and now in operation over the last two years, at the Australian Centre for Neutron Scattering, in Sydney, five tonnes of high density radiation shielding surrounds the ~ 1m^3 stainless steel vacuum chamber that houses around 300 kg of filter block material. The entrance and exit windows of the spectrometer consist of an arc of 4mm thick Al-alloy material. The filter blocks are arranged within the vacuum chamber in arcs directed along the neutron scattering arc and consist of banks of Bismuth, Graphite and Beryllium. For the spectrometer to operate properly, that is to filter out neutrons greater than 1.8 meV, all filter blocks are cooled to below 80K through cryogenic refrigeration that is based ona closed-loop helium expansion cycle. Two vacuum cryogenic refrigeration systems are connected to the vacuum chamber. Each identical system consists of a compressor package, which compresses refrigerant and removes heat from the system as well as the cold head itself, which takes refrigerant through one or more additional expansion cycles to cool it down to cryogenic temperatures (< 20K). The filter blocks are attached to this cooling system through oxygen free copper braids and connecting plates and frames. When in operation, under a vacuum of ~2x10-8 mbar, the filter blocks reach a temperature of 80K and better within 48 hours. The filter spectrometer has been used in thisstate for months without degradation of vacuum or temperature of filter blocks. Finite element analysis is presented for the structural integrity of the vacuum chamber as well as the heat transfer expected for the cryorefrigeration system. Deflection, pump down and cool down results are given for comparison. All in all the design performs very well allowing for seamless continuous operation to be achieved.

Summary:

Poster Session - Main Hall Tuesday / 134

Field emission arrays characterised by x-ray photoemission electron microscopy

Anton Stampfl1 ; Robert Winarski2

1 Australian Nuclear Science and Technology Organisation 2 Argonne National Laboratory

Corresponding Author(s): [email protected]

The phenomenon of field emission has been known for some 100 years with cold emission electron sources being exploited for their high brightness in fine-focus applications such as microscopy, high- density information recording, micro-fabrication, flash x-ray devices, and flat panel displays. The last decades has witnessed a renaissance in materials development and potential use of these devices. And yet much of the familiar questions that seek to relate emission quality with surface structure and chemistry remain unanswered. Photoemission microscopy using soft x-rays produced from a synchrotron has the potential to revolutionise the characterization of many aspects of field emission devices because both emission character and surface structure and chemistry may be directly obtained and correlated. This study reports some of the first steps towards such a goal. Fieldinduced emission character, chemical composition, and morphology of low work-function Cu-Li/Si arrays are spatially studied and correlated. Results clearly show highest emission occurs at the sharpest edges of the structures that are covered by the alloy, thus opening the door for systematic studies into fundamental structure-function problems of such advanced functional materials under operating conditions.

Summary:

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Poster Session - Main Hall Tuesday / 131

The electronic structure of S-layer proteins from Lactobacillus brevis

Anton Stampfl1 ; Susan Graham2 ; Richard ClementsNone ; Nicola Asquith2 ; Wilde Karyn2 ; Yeukuang Hwu3

1 Australian Nuclear Science and Technology Organisation 2 ANSTO 3 Academia Sinica

Corresponding Author(s): [email protected], [email protected]

Bacterial S-layers present an interesting composite material to study. S-layers are crystalline outer- sheaths of some bacteria that consist of a number of proteins. Unit cells are essentially two-dimensional with lattice parameters that are in the order of nanometers. This study attempts to detail theelec- tronic structure from one particular bacterium, Lactobacillus brevis. L. brevis is a rod-shaped gram- positive bacterium from the family of lactic acid bacteria, Lactobacillaceae, that are involved in the fermentation process creating CO2 and lactic acid. Clearly the surface of such bacteria must play a huge role in such heterogeneous fermentation processes. The valence electronic structure of theS- layer of L. brevis is determined using synchrotron-based photoelectron spectroscopy and soft x-ray absorption spectroscopy. Spectra are compared to experimental work on amino-acids and S-layers of Bacillus sphaericus. While indeed possible to identify energy levels with those of natural amino- acids, distinct energy shifts are observed which cannot be reconciled using such simple comparisons. Furthermore a strong nitrogen signal observed in both the occupied and unoccupied energy levels suggests that the L. brevis protein is amine-terminated on the S-layer surface. The presence of amine termination suggests decarboxylase activity related to the fermentation process.

Summary:

Speaker Sessions and Seminars / 88

Rational Design of Nano-Catalysts for Sustainable Chemicals and Fuels: Insights from Theory and Simulation

Catherine Stampfl1

1 The University of Sydney

Corresponding Author(s): [email protected]

With the ever increasing consumption of the world’s fossil-fuel resources due to the rapid development of industry, as well as climate change which is mainly induced by a surge in CO2 concentration in the atmosphere, both energy and environmental issues are two key problems facing humanity[1]. Over the last decade there has consequently been a substantial increase in innovative utilization of renewable and environmentally benign energy resources. In particular, with the globally increasing socio-political pressure to reduce CO2 emissions, CO2 has become a promising carbon source with a zero or even negative cost and practically unlimited availability for sustainable chemical manufacturing of hydrocarbon fuels and their derivatives. Central to further advancement in the creation of renewable and benign energy sources and environmental protection, is the breakthrough developments of new nanocatalysts. In the present talk, an over-view and recent results based on first-principles theory calculations, in synergy with experiment will be presented for several key catalytic reactions. These include, the dry reforming of methane with carbon dioxide over a nickel based composite catalyst, conversion of methane and carbon dioxide to the higher value product chemical acetic acid over metal-exchanged zeolites[2], as well as ammonia synthesis from nitrogen reduction over graphitic carbon nitride[3].

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Finally, results will be presented illustrating how theory and computation can aid in the screening of candidate materials for particular desired functionalities. 1 G. A. Olah, G. K. S. Prakash, A. Goeppert, Journal of the American Chemical Society 2011, 133 (33), 12881-12898. 2 P. Zhang, X. Yang, X. Hou, J, Huang, C. Stampfl, to be submitted. 3 H. Liu, P. Wu, H. Li, Z. Chen, X. Zeng, Y. Zhu, Y. Jiang, X. Liao, B. Haynes, J. Ye, C. Stampfl, J. Huang, submitted.

Summary:

Poster Session - Main Hall Tuesday / 252

Protein-functionalised plasma activated coatings for orthopaedic applications

Callum Stewart1 ; Behnam Akhavan2 ; Juichen Hung3 ; Shisan Bao4 ; Steven Wise5 ; Jun-Hyeog Jang6 ; Marcela Bilek2

1 The University of Sydney 2 School of Aerospace, Mechanical and Mechatronic Engineering & School of Physics, University of Sydney, NSW 2006, Australia 3 Heart Research Institute 4 Charles Perkins Centre 5 Heart Research Institute and Sydney Medical School 6 School of Medicine, Inha University

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

The prevalence of orthopaedic implants has greatly increased worldwide. In Australia alone, forex- ample, close to a million total hip and knee replacement operations have been performed since 1999, around 10% of which required revision surgeries due to problems associated with poor bone integration. Protein-functionalisation of titanium for load-bearing orthopaedic applications is a strategy being explored to facilitate optimal bone integration. Plasma polymerisation is a dry, versatile, and largely substrate-independent process to produce thin films suitable for protein immobilisation. In our work, we utilise a combination of plasma polymerisation and energetic ion bombardment to em- bed high quantities of radicals into the plasma polymerised coating for the covalent immobilisation of proteins. This novel method of protein immobilisation removes the need for further wet-chemical steps. Fibronectin (FN), osteocalcin, (OCN), a mixture of FN: OCN in a ratio of 1:3 respectively (FN:OCN), and an FN-OCN fusion protein (Fusion) were covalently immobilised onto rPPF-coated Ti substrates. Mouse primary osteoblasts (mOB) were utilised for the analysis of cell attachment (DAPI) and spreading (F-Actin) after 1 hour, and the cell mineralisation (alizarin red) after 17days. Significant increases in both attachment (cell number) and spreading (cell size) were observed onthe ratio- and the fusion -functionalised surfaces compared to bare Ti and rPPF. A significant increase in cell mineralisation was found on the fusion-functionalised surface only compared to Ti, rPPF, and OCN. We have demonstrated that multifunctional protein surfaces can be fabricated on rPPF-coated Ti substrates for improved osteoblast activity, thereby, demonstrating a potential to reduce the need for revision surgeries.

Summary: In this work, we present the investigation of novel proteins for the biofunctionalisation of titanium, focussing on implantable biomedical devices. The proteins are covalently attached to the surface through imbedded radicals into a plasma polymerised thin films (rPPFs). Osteoblasts demonstrated a significant increase in the attachment to protein-functionalised surfaces compared to bare Ti or rPPFs alone, and highly significant mineralisation on the fusion protein-functionalised.

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Speaker Sessions and Seminars / 261

Towards ARPES at the Australian Synchrotron: 3rd Generation Toroidal Angle Resolving Electron Energy Spectrometer

Anton TadichNone

Corresponding Author(s): [email protected]

Angle Resolved Photoelectron Spectroscopy (ARPES) is the “complete” photoemission experiment. It simultaneously measures a photoelectron’s kinetic energy, emission angle and sometimes spin, relative to the crystallographic axes, constructing a direct image of the electronic bandstructure. This makes ARPES the most powerful contemporary technique for determining the electronic structure of novel materials. ARPES has been instrumental in the discovery and understanding of new electronic phases of matter. For example, important aspects of the electronic structure of high-Tc superconductors, such as the pseudogap were discovered using ARPES, as was the experimental discovery of three dimensional topological insulators Bi1-xSbx and Bi2(Se,Te)3. Over the years, a dramatic improvement in the energy and momentum resolution possible with ARPES has occurred as a result of advances in photoelectron analysers and 2D detectors, allowing a range of new physics to be probed. Despite the popularity of ARPES overseas, within Australia it has until now remained as a niche technique due to a small (albeit dedicated) user community. However, the continually growing local interest in studying novel materials with exotic electronic properties has led to the demand for our own synchrotron – based ARPES instrument. Here, an overview of a forthcoming ARPES instrument, an advanced 4th generation “toroidal” electron spectrometer,at the Australian Synchrotron will be given. An advanced helium discharge lamp allows for offline work to be carried out. In contrast to the previous 3rd generation instrument installed at BESSY2, the 4th generation Toroidal Analyser is equipped with a liquid helium cryostat and radiation shielding to allow for ARPES measurements to be conducted with the sample at cryogenic temperatures. An overview of the system’s principles of operation, and sample preparation environment will be given.

Summary:

Poster Session - Main Hall Tuesday / 83

Rapid thermal annealing effect on characterizations of CNW on Si substrate by chemical vapor deposition

Author(s): lee taehwan1

Co-author(s): Seungcheol yoo 2 ; Sejin Jung 2 ; Soojung Jang 1 ; Wonseok Choi 1 ; Hyunil Kang 2

1 Hanbat National University 2 Hanbat National University,

Corresponding Author(s): [email protected], [email protected]

In the research, Carbon nano wall (CNW) is synthesized by chemical vapor deposition on polyimide substrate. The effect of gas ratio of on the structure, and electrical properties of CNWhasbeen studied. Scanning electron microscope(SEM) studies of the diameter of CNW synthesized under various gas ratios were measured. The surface and cross section of CNW were analyzed by SPMand FE-SEM. Raman spectroscopy was used to determine the difference in crystalloid with growth time, which was quantified by the ratio of ID / IG. Resistance characteristics were analyzed to analyzethe electrical characteristics of CNW.

Summary:

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Poster Session B / 51

Photodesorption and Photoelectron Yields from Thin Film Coat- ings at Cryogenic Temperature

Yasunori Tanimoto1 ; Roberto KersevanNone ; Paolo ChiggiatoNone ; Tohru HondaNone ; Marton AdyNone

1 KEK

Corresponding Author(s): [email protected]

Title: Photodesorption and Photoelectron Yields from Thin Film Coatings at Cryogenic Tempera- ture Abstract: In the design of particle accelerators, for a precise estimation of the pressure profile along the beam chambers, it is essential to adopt an appropriate data of photon-stimulated desorption (PSD) yields into vacuum simulators, such as a combination of Synrad and Molflow. Additionally, in the design of proton or positron accelerators, it is required to cope with the electron cloud issues while taking account of an appropriate photoelectron yield (PEY) of the beam chambers. These PSD and PEY data should therefore be measured experimentally under similar conditions to the machines being designed, in terms of the energies of Synchrotron Radiation (SR), materials and surface treatments of vacuum chambers, incident angles of SR, etc. At CERN, a design study of the 100 TeV proton-proton collider named FCC-hh has been carried out under worldwide collaboration, and KEK has undertaken the PSD and PEY measurements using an SR beamline at Photon Factory, where SR with a critical energy of 4.0 keV is available. In FCC-hh, the beam screen will be operated at cryogenic temperatures ranging from 40 to 60 K while being irradiated by SR with a critical energy of 4.3 keV. In our previous measurements at room temperature, two thin film coatings, namely Non- Evaporable Getter (NEG) coating and amorphous carbon coating, were verified to have a sufficiently low PEY, and the NEG coating to have a sufficiently low PSD yield. For the FCC-hh study, these two possible coatings have been examined at a cryogenic temperature of 77 K while being cooled with liquid nitrogen, and it was found that not only the NEG coating but also the carbon coating exhibited sufficiently low PSD yields. These systematic measurements enabled us to verify and discussthe effect of the cryogenic temperature on the PSD and PEY properties of the thin film coatings.

Summary:

Speaker Sessions and Seminars / 59

Dependence of Thermal Conductivity of MPCVD Diamond Thin Films on Oxygen Concentration

Fatima Tuz Zahra1 ; James Downes1

1 Macquarie University, NSW 2109, Australia

Corresponding Author(s): [email protected], [email protected]

There are various applications for which diamond thin films (DTFs) have gained attention dueto their unique physical properties including good optical properties, high thermal conductivity, high electrical conductivity etc. The most prominent among all is the high thermal conductivity ofdia- mond which makes it a potential candidate for heat spreading and other such applications in the field of electronics. To date, various methods have been introduced to enhance the abovemen- tioned properties of the diamond thin films which typically involve doping, and variation in process parameters. In presented study, a series of DTF samples was prepared at 750℃ with different oxygen concentrations. Microwave plasma chemical vapour deposition (MPCVD) method was used for sample preparation at different process parameters (H2 flowrate (99 sccm), CH4 flowrate (1sccm), Power (600W), Gas pressure (20 Torr), substrate temperature (750℃), deposition time (24 hours)), which were kept constant during film deposition. The effect of variation in oxygen concentration on structural, morphological, and thermal transport properties of diamond have been studied. For

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structural analysis of the prepared samples, Raman spectroscopy was used which confirmed the formation of good quality DTFs. The addition of oxygen to the growth enhanced the crystallinity and morphology of the samples which was revealed by scanning electron microscopy (SEM). Moreover, morphological analysis showed that the growth of the (100) facet was enhanced for DTFs prepared at low oxygen concentration. Sample thermal conductivity was also analysed by utilizing Raman thermography and these results were correlated against growth conditions. It was found that, the structural features, morphology and thermal conductivity of the samples were correlated with each other.

Summary:

Speaker Sessions and Seminars / 16

An ex situ near edge X-ray absorption fine structure spectroscopy study of metal phthalocyanine catalysts for CO2 reduction

Jean-Pierre Veder1 ; Yi Cheng1 ; Shiyong Zhao1 ; San Ping Jiang1

1 Curtin University

Corresponding Author(s): [email protected]

The electrochemical reduction of CO2 is a process that has attracted considerable attention dueto the combined benefits associated with the environmental remediation of CO2 and the production of valuable feedstock materials (e.g. CO) for the production of liquid fuels [1]. We have been studying the use of molecular catalysts such as metal phthalocyanines (MPc) as desirable candidates for CO2- to-CO electrochemical catalysis as they can be tuned to achieve high activity and selectivity over proton reduction. In particular, iron phthalocyanine (FePc) is particularly interesting because the Fe(0) centre can donate electrons in the activation of CO2 molecules and exhibits a relatively low onset potential for CO2 reduction when compared with other metal phthalocyanine systems. Recently, we observed that the addition and self-assembly of metal-oxide nanoclusters (MOx, where M = Ni or Co) on FePc catalysts can result in improved catalytic performance compared to the neat material [2]. Ex situ near edge X-ray absorption fine structure (NEXAFS) measurements were performed on the catalyst materials as a function of applied potential during CO2 reduction. Remark- ably, the NEXAFS investigation revealed that at certain potentials, electrochemical substitution occurs between the active iron centre in FePc with the Ni or Co from the MOx nanoclusters. In this presentation, details of the ex situ NEXAFS investigations will be presented, in addition to transmission electron microscopy, atomic force microscopy and electrochemical results that demonstrate improved electrocatalytic performance. References: [1] Wilhelm D., Simbeck A., Karp R., Dickenson R., Fuel Process Technol. 71, 139 (2001). [2] Cheng Y., Veder J.-P., Thomsen L., Zhao S., Saunders M., Demichelis R., Liu C., De Marco R.,Jiang S.P., J Mater. Chem. A 6, 1370 (2018).

Summary:

Speaker Sessions and Seminars / 6

Oxygen Reduction Reaction Activity for Pt/Zr/Pt(111) Model Cat- alyst Surfaces Prepared by Arc-plasma deposition

Soma Kaneko1 ; Daisuke Kudo1 ; Shuntaro Takahashi1 ; Naoto Todoroki1 ; Toshimasa Wadayama1

1 Graduate School of Environmental Studies, Tohoku University

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Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected]

Oxygen reduction reaction (ORR) activity enhancement mechanisms of Pt-based alloy (Pt-M) catalysts is a key for developing highly-efficient cathode catalysts for polymer electrolyte fuel cell.In particular, the relation between the outermost structure of the Pt-M catalysts and electrochemical (EC) properties, e.g., ORR activity is a key issue. In this study, ORR activities are investigated for Pt/Zr model catalysts prepared on Pt(111) substrate through alternative arc-plasma depositions (APD) of Pt and Zr nano-meter-thick-layers. The UHV-APD-EC apparatus is described elsewhere [1]. Nano-meter-thick Pt and Zr layerswere alternately deposited onto a clean Pt(111) substrate by the APD method. Structural analysis for the prepared model nano-structures are performed by using in-plane XRD, cross-sectional STEM. For the ORR activity evaluation, the UHV-prepared samples were transferred to an N2-purged glove box without air exposure. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were conducted in N2-purged and O2-saturated 0.1M HClO4 in the glove-box. Surface strain that estimated by the in-plane XRD depended on the deposition thickness ratios of Pt and Zr layers: tensile strain worked on the topmost Pt(111) shell. Estimated ORR activity enhancement factors vs. clean Pt(111) are determined by the tensile surface strain and chemical effects of the topmost Pt(111) layers induced by underlying Zr. We wish to acknowledge the NEDO of Japan. [1] S.Kaneko et al., JPCLett. 8, 5360 (2017).

Summary:

Poster Session - Main Hall Tuesday / 260

Hydrogel coating for biomedical devices covalently attached by means of plasma immersion ion implantation

Author(s): Rashi Walia1

Co-author(s): Behnam Akhavan 1 ; Elena Kosobrodova 1 ; Alexey Kondyurine 1 ; Sina Naficy 2 ; Fariba Dehghani 1 ; Marcella Bilek 3

1 University of Sydney 2 university of Sydney 3 University of Sydney

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Hydrogel materials are attractive for a wide range of applications such as tissue engineering, wound healing, controlled drug release, contact lenses, water treatment, biosensors, regenerative medicine as well as in cosmetics. Hydrogels are an ideal medium for promoting optimum biological integration. They provide a suitable environment for attachment and cell growth with good transportation of oxygen and nutrients as well as metabolic substances and cellular waste. They are hydrophilic and mimic the native extracellular matrix. Hydrogels are soft so they cannot be used directly for applications where mechanical integrity is required, such as in bone implants. However, they could be attached to solid substrates that provide mechanical strength and desired shape. In this research, stable solid-hydrogel hybrid structures are developed through plasma immersion ion implantation (PIII) of PTFE (Teflon) and polystyrene. Acrylamide monomer was polymerized on the PIII activated surfaces and formed covalent bonds with surface-embedded radicals without any external crosslinking agents or initiators. The amount of hydrogel formed on the substrate increased with the incubation time, monomer solution temperature and concentration. The stability test results indicated that 95% of the hydrogel coating was retained on the surfaceeven after 4-month incubation in PBS solution. Adhesive T-peel tests were performed, demonstrating an adhesion strength of hydrogel on the PIII-treated PTFE interface of 300-340 N/m. The surface chemistry of untreated, PIII treated, and hydrogel-attached PTFE samples were investigated using X-ray photoelectron spectroscopy (XPS) and attenuated total reflection (ATR)-Fourier transform infrared

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spectrometry (FTIR). The surface chemistry analyses confirmed the formation of acrylamide hydrogel on the surface. The wettability of the samples was evaluated using water and diiodomethane contact angle measurements, confirming the hydrophilicity of the hydrogel attached surfaces. The water and diiodomethane contact angles were 126.190 and 106.60, respectively for PIII-treated PTFE. With attached hydrogel, the contact angles varied as a function of hydrogel coating thickness, in the range 96.90-52.20 for water and in the range 107.50 -16.780 for diiodomethane. The significantly lower contact angle measured for the hydrogel coatings also confirmed the formation of hydrogel on the solid substrates. Our results show that PIII-treated polymers provide excellent solid platforms for the creation of robust solid-hydrogel hybrid structures.

Summary:

Plenary / 138

Graphene – Cellular Interactions and Implications for Medical Device Technologies

Gordon Wallace1

1 University of Wollongong

Corresponding Author(s): [email protected]

Graphene is an extraordinary material with a combination of properties including electrical conductivity, exceptional strength and biocompatibility that makes it attractive in a number of areas of application.

Careful control of all steps from sourcing the graphite, to exfoliation and chemical modification of graphene sheets, is important in rendering the dispersions obtained amenable to subsequent fabrication such as spray coating, printing or fiber spinning.

Recent advances in our laboratories have involved the development of chemistries that retain the inherent properties of graphene while rendering it processable in aqueous or organic solvents.

Chemistries developed here have also enabled effective formation of graphene containing composites that are amenable to fabrication.

Success in these areas has led to the application of graphene and structures containing it, for energy storage and conversion, as well as in biomedical areas including neuronal recording and stimulation electrodes, as well as scaffolds for bone regeneration. As part of this presentation a critical non-technical requirement will be discussed: the need for a collaborative interdisciplinary approach to ensure effective and efficient progress.

Summary:

Speaker Sessions and Seminars / 74

Modelling Driven Discoveries in Molecular Spectroscopy

Feng Wang1

1 Swinburne University of Technology

Corresponding Author(s): [email protected]

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A significant number of scientific discoveries in the past was driven by experiment with severalex- ceptions. The coming industry 4.0 era will be digital and computer simulation driven. Physical properties of almost all materials should be predictable, in principle, by solving the quantum-mechanical equations governing their constituent electrons. Such calculations require only a small number of chemical elements in appropriate positions through forces. This presentation will cover a broach spectrum of simulation driven discoveries in recent years at Swinburne University through international collaboration. In particular, the narrative of research collaboration leading to breakthrough of the structure of ferrocene using IR spectroscopy will be presented (University of Melbourne and Australian Synchrotron). The X-ray photoemission spectroscopy (XPS) of biomolecules in collaboration with Elettra-Sincrotrone, Trieste (Italy) will be discussed. I will also present primary results of the recent development on interactions between single molecule and metal surfaces.

Summary: The work to be presented is multidisciplinary. It can cover functional material, renewable energy, bioactive compounds, rational drug design, catalysis and single molecule and surface interaction etc. It combined theory and experiment through international collaboration.

Speaker Sessions and Seminars / 259

Zero resistance materials and technologies

Xiaolin Wang1

1 University of Wollongong

Corresponding Author(s): [email protected]

Electrical power consumption occurs because of the resistance to the flow of electrical current. The power lines and transformers as well as information and computation consume more than 20% of the world’s electricity. In this presentation, we will discuss the latest development on superconductors and emerging materials in which electrical current can flow without resistance for ultra-low energy consumption technology. A number of emerging electronic materials such as topological insulators, parabolic or Dirac type spin gapless semiconductors (SGSs), Weyl metals with exotic band structures, Dirac type systems or topological Dirac system, and excitonic insulators will be discussed. How to achieve zero resistance transport in spin gapless semiconductor and topological insulators will be presented. Realization of emerging quantum effect such as quantum Hall, Quantum anomalous Hall, quantum spin or quantum anomalous spin Hall effects will be discussed. A few emerging technologies which can drive 2D systems into zero resistance state will be discussed. Furthermore, the ultimate questions in material and property’s design are raised: 1) How many new electronic materials or new electronic properties are still there? 2) What are they? 3) How to create them? I will present a number of new strategies we have developed for the design of new class of materials and properties. We will discuss how new electronic materials can be designed by shaping electronic band structures. To answer the three questions, a very simple model, the codes of matter/materials, based on the three ubiquitous and paramount attributes of all existing matter/materials, charge (Q), spin (S), and moment (K) is introduced. We will introduce a new periodic table which consists of all codes responsible for physical properties. The principles of the codes and their applications in design of new materials and properties will be presented. Many new types of exotic physical states and their possible experimental realizations will be discussed. This work is supported by Australian Research Council (ARC) through the ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET) and an ARC Professorial Future Fellowship project (FT130100778).

Summary:

Plenary / 176

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Dark Secrets of the Universe

Fred Watson1

1 DIIS

Corresponding Author(s): [email protected]

Aside from the search for extraterrestrial life, the biggest questions confronting astronomers today relate to two fundamental properties of the Universe. Despite their similar names, dark matter and dark energy have vastly different attributes. The nature of both is unknown, yet together they consti- tute 95 percent of the Universe’s mass-energy budget. In this talk, astronomer Fred Watson reviews the observational evidence relating to dark matter and dark energy, and highlights some of the work being carried out to understand their origin.

Summary:

Speaker Sessions and Seminars / 96

Development of scalable plasma polymerisation processes

Jason Whittle1

1 University of South Australia

Corresponding Author(s): [email protected]

Plasma technology has been used to produce cell culture plastics since the 1960s, but more recently, functionalised surfaces have been developed that provide specific functional groups for immobilisation, or for capturing biomolecules. While these surfaces can be made simply and easily in the lab, producing them at a commercial scale presents a number of challenges. We present the development and characterisation of a large-area plasma polymerisation pilot reactor system capable of higher throughput than typical lab-scale reactor systems and describe some of the challenges in scaling up plasma systems of this type. The system is compared with a standard lab-scale system using plasma mass spectrometry, ion flux measurements and characterisation of the products be XPS and ToF-SIMS.

Summary:

Speaker Sessions and Seminars / 144

Key Materials Issues in Co-Sputtered Aluminium-Gallium Oxide Films and Their Applications to Solar-Blind Photodetectors

Dong-Sing Wuu1 ; Chao-Chun Wang2 ; Shuo-Huang Yuan1 ; Shiau-Yuan Huang1

1 Department of Materials Science and Engineering, National Chung Hsing University 2 Department of Materials Science and Engineering, National Chung Hsing Uiversity

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

A wider bandgap material possesses great merit as it allows the design of devices such as high sensitive wavelength-tunable photodetectors (PDs). Aluminum element is a candidate to enlarge the bandgap of Ga2O3 since Al2O3 has a larger bandgap. The similar electron structures of Al and Ga makes the (AlGa)2O3 alloy possible to achieve. Therefore, by incorporating Al2O3 into Ga2O3, the bandgap of aluminum-gallium oxide (AGO) materials can be modulated toward a higher value

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(commonly 5~7 eV), which expands its deep ultraviolet (DUV) applications. In this study, the wide- bandgap AGO thin films were grown on sapphire by co-sputtering of Al and GaO targets, which were used DC and RF powers, respectively. The RF power for the GaO target was fixed at100W. Various DC powers of 5, 10, 30, 50, and 70 W were employed for the Al target. The substrate temperature and AGO thickness were kept at 600 C and 120 nm, respectively. Moreover, the pure Ar and O2 gases were introduced into the growth chamber at a constant [O2/(Ar + O2)] partial pressure of 16%, and the working pressure was fixed at 5 mTorr. Additionally, the as-deposited AGO films were annealed at 900 C for 20 min in air. The AGO films deposited at the Al sputtering power of5-50W presented single crystalline phase with AGO(-201)-family diffraction peaks. However, as the Al sputtering power was increased to 70 W, the AGO film was amorphous. In addition, the energy gap (Eg) values can be obtained via their transmittance spectra. As the Al sputtering powers were 5, 10,30, 50, and 70 W, the Eg values of AGO films were determined to be 5.06, 5.10, 5.13, 5.19, and 5.24 eV, respectively. Furthermore, the AGO films grown at the Al sputtering power of 5-30 W were selected to prepare the metal-semiconductor-metal PDs. As a 20-V bias was applied, the device fabricated with AGO film using the Al sputtering power of 10 W has better performance, where its darkcurrent and responsivity are 1.8 × 10−12 A and 0.37 A/W, respectively. By adjusting the growth conditions of AGO films, the performance of PDs will be improved and presented in thiswork.

Summary:

Poster Session B / 32

Pyrite oxidation: a comparative study of chemical and air oxidation

Shihong Xu1 ; William Skinner1

1 Future Industries Institute, University of South Australia

Corresponding Author(s): [email protected], [email protected]

Pyrite oxidation, a common process in nature, is of great concern to many environmentally and eco- nomically important topics, including formation and control of acid mine drainage (AMD), ecological cycle of sulfur, beneficiation of sulfide ores and extraction processing of gold. In order to investigate pyrite oxidation related matters in laboratories, numerous artificial oxidation methods have been proposed. Chemical oxidation by hydrogen peroxide solution and air oxidation by exposing pyrite to atmosphere are two commonly used artificial oxidation methods. However, no comparative work has been conducted on these two methods. In this work, chemical oxidation where fresh pyrite plates are conditioned with hydrogen peroxide solution (0.03% and 3% wt/v) for different time periods and natural air oxidation where fresh pyrite plates are exposed to atmosphere for periods of months (1, 2, 3 and 5 months) at room temperature were tested. The types of oxidation species, their relative contents, and the thickness of the oxidation layer on these two kinds of oxidised pyrite surfaces were characterized and compared using X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The surface chemistry data extracted from XPS and AES results of these pyrite were also correlated with their hydrophobicity, presented as contact angle.

Summary:

Poster Session - Main Hall Tuesday / 98

Fabrication of gasotransmitter releasing amphiphilic copolymeric nanoparticles

Chungmo YangNone ; Kyuchul Lee1 ; Min Hee Park1 ; Kangwon Lee1

1 Seoul National University

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Corresponding Author(s): [email protected], [email protected], [email protected]

The amphiphilic polymers can be used to nano-structured materials because of its both characterizations of hydrophilicity and hydrophobicity. When the polymer exists in an appropriate concentration, the polymers perform distinct self-assembled structures such as sheet, micelles, and poly- mersomes. The polymeric nanoparticles have emerged in drug delivery systems since it iseasyto prepare and encapsulate drug. mPEG-PLGA is representative of biodegradable and biocompatible polymer which has hydrolysis property and low toxicity against human cells and tissues. Since the co-polymer has amphiphilic which can be easy to form various self-assembled structures, we synthesized and prepared co-polymeric nanoparticles having bi-layered using amphiphilic co-polymers. Nitric oxide (NO) and Hydrogen sulfide (H2S), as well as carbon monoxide (CO), is called “gasotransmitter” and they do mediate various physiological functions. NO is endogenously produced bynitric oxide synthase and convert GTP to cGMP and it stimulates protein kinase G (PKG). PKG provides the signals to regulate physiological functions through controlling ion channels. H2S can inhibit PDE5A that can degrade cGMP. By inhibiting degradation of cGMP, NO signals can be ultimately amplified by H2S. In this study, Co-delivery system with NO and H2S has been proposed via biocompatible and biodegradable polymers; poly(ethylene glycol-b-lactic-co-glycolic-co-hydroxymethyl propionic acid) (functionalized PLGA). The NO-releasing polymers were synthesized by S-nitrosation reaction can form S-nitrosothiol and then, encapsulating GYY4137 as an H2S releasing agent. The nanoparticles exhibited slow releasing behavior, low cytotoxicity and accelerating tube formation. These results provide feasibility of medical applications through NO and H2S crosstalk.

Summary: The nanostructured polymeric nanoparticles for biomedical applications.

Speaker Sessions and Seminars / 137

Neutron studies of iron-based superconductors

Author(s): Jie-Yu (Shirley) Yang1 Co-author(s): Anton Stampfl 2 ; Chin-Wei Wang 3 ; Richard Clements ; Kuo-Chung Huang 1 ; Chin-Han Wang 1 ; Chih-Hao Lee 4 ; Maw-Kuen Wu 1

1 Institute of Physics, Academia Sinica, Taipei, Taiwan 2 Australian Nuclear Science and Technology Organisation 3 National Synchrotron Radiation Research Center, Taiwan 4 Engineering and System Science, National Tsing Hua University, Taiwan

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

The study of magnetic structure and neutron scattering on potassium intercalated iron selenide (K2Fe4Se5) and its doped system (K1.9Fe4+x-yAySe5, A=Cu/Mn) is presented here. An intriguing phenomena is observed in the magnetic properties due to doping, which could provide different view to the mechanism of superconductivity. Excess iron in the Fe-chalcogenide family, appears to somehow induce Fe-vacancies from an ordered to a disordered state which may be the origin of superconductivity. In this study, extra iron dopants induce superconductivity in the parent compound, K2Fe4Se5, while extra manganese and copper doping suppresses superconducting behavior. The long range magnetic ordering temperature (TN) is confirmed to be lower than the Fe-vacancy order- to-disorder temperature (TVO). Anisotropic transport properties are shown to exist in K2Fe4Se5 [1]: the interlayer properties playing an important role in superconductivity. Manganese and copper substitution of iron sites, however, induce the shift of the superconducting critical temperature and the suppression of superconductivity due to the change in competition between anti-ferromagnetism and superconductivity in this 245 system [2-3]. Reference [1] Y. J. Song, Z. Wang, Z.W. Wang, H. L. Shi, Z. Chen, H. F. Tian, G. F. Chen, H. X. Yang and J. Q. Li, European Physics Letter, 95, 37007 (2011) [2] Tzu-Wen Huang, Ta-Kun Chen, Kuo-Wei Yeh, Chung-Ting Ke, Chi Liang Chen, Yi-Lin Huang,

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Fong-Chi Hsu, Maw-Kuen Wu, Phillip M. Wu, Maxim Avdeev, and Andrew J. Studer, Physical Review B 82, 104502 (2010) [3] Dian Tan, Changjin Zhang, Chuanying Xi, Langsheng Ling, Lei Zhang, Wei Tong, Yi Yu, Guolin Feng, Hongyan Yu, Li Pi, Zhaorong Yang, Shun Tan, and Yuheng Zhang, Physical Review B 84, 014502 (2011)

Summary:

Poster Session - Main Hall Tuesday / 114

Characteristics of superimposed dual-frequency inductively coupled plasma source

Soo Gang Kim1 ; Kyung Chae Yang1 ; Geun Young Yeom1

1 Sungkyunkwan University

Corresponding Author(s): [email protected]

Some of the important specifications for next generation plasma etch systems are the ultra-high etch selectivity and the extremely high uniformity control on the substrate. Especially for inductively coupled plasma (ICP) sources, as the power to the ICP sources is increased for increased plasma density, non-uniform power deposition resulting in non-uniformity of the plasma is increased further. In this study, as one of the methods in controlling the plasma uniformity, superimposed multi-frequency operation on an ICP source has been investigated. When using dual-frequency operation of the ICP source, an improved plasma uniformity could be observed. On the ICP source, dual frequency power (2MHz and 13.56MHz) was applied and, on the substrate, a single frequency (12.56MHz) bias voltage was applied. To examine the role of low frequency source in affecting the uniformity, both single frequency and dual superimposing frequency were compared. It is found that, using superimposed frequency, the plasma distribution and voltage waveform inside the chamber are changed and they affect overall properties of the plasma.

Summary:

Speaker Sessions and Seminars / 127

Confinement-Induced Giant Spin-Orbital-Coupled Magnetic Mo- ment of Co Nanoclusters in TiO2 Films

Jiabao Yi1 ; Xiang Ding2 ; Xiangyuan Cui3 ; Chi Ciao4 ; Xi Luo2 ; Nina Bao4 ; Andrivo Rusydi4 ; Zunming Lu3 ; Yonghua Du5 ; Xingwei Guan6 ; Li-Ting Tseng2 ; Wai Tung Lee7 ; Sohail Mahamd2 ; Rongkun Zheng3 ; Tao Liu8 ; Tao Wu2 ; Jun Ding4 ; Kiyonori Suzuki9 ; Valeria Lauter10 ; Simon P. Ringer3

1 University of Newcastle 2 UNSW 3 University of Sydney 4 National University of Singapore 5 Institute of Chemical and Engineering Science, A*star, Singapore 6 King Abdullah University of Science and Technology 7 ANSTO 8 Karls Tech GmbH, Germany 9 Monash University 10 Oak Ridge National Lab

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Corresponding Author(s): [email protected]

High magnetization materials are strongly required for the fabrication of advanced multifunctional magnetic materials and devices, whereas, the development of high magnetization materials is extremely slow. In this work, we propose a new strategy to achieve high magnetization above room temperature by nanoengineering. In detail, 5% Co-TiO2 film has been deposited using pulsed laser deposition. By delicately controlling deposition parameters, Co clusters are formed and further confirmed by transmission electron microscopy, energy dispersive spectroscopy and X-ray absorption near edge spectroscopy. The film exhibits a very high saturation magnetization measured bymag- netometer, equivalent to 6.54 B/Co, given that the magnetic moment is all contributed from Co dopant. However, X-ray magnetic circular dichroism indicates that Co only has a magnetic moment of 3.5 B. The rest of the moments are contributed from Ti and O. First principles calculations demonstrate that metallic Co nanoclusters embedded in TiO2 matrix can have large both spin and orbital moments, consistent with experimental results. The work indicates that very small nanoclusters under confinement environment can exhibit very large magnetic moments above room temperature, which is promising for designing artificial high magnetization materials.

Summary:

Speaker Sessions and Seminars / 100

High resolution and radiation-damage free inverse photoelectron spectroscopy

Hiroyuki Yoshida1

1 Chiba University

Corresponding Author(s): [email protected]

Despite the importance, limited information has been available about the unoccupied states of organic semiconductors because of lack of a suitable experimental technique. Inverse photoelectron spectroscopy (IPES) is, in principle, an ideal tool to examine the unoccupied states; the electrons are introduced to the sample surface and the photons emitted due to the radiative transition toun- occupied states are detected, which can be regarded as the time-inversion process of photoelectron spectroscopy (PES). Particularly, to determine quantitatively the energies of the unoccupied states of such systems with large exciton binding energy as organic semiconductors, IPES can be a unique technique. In the previous IPES, however, the sample damage to the molecules was unavoidable owing to the electron bombardment and the energy resolution was limited to 0.5 eV.

In 2012, we developed low-energy inverse photoelectron spectroscopy (LEIPS) [1]. In order to reduce the sample damage, the kinetic energy of incident electron is lowered to less than 5 eV which is a typical damage threshold of the organic materials. By reducing the electron energy, the photons emit in the near-ultraviolet range leading to the improvement of energy resolution for the photon detection using the multilayer bandpass filters. Using LEIPS, the unoccupied states can be examined with the accuracy similar to the occupied states using PES.

This novel technique has been applied to organic semiconductors relevant to organic electronic devices [2] and to the fundamental research of organic semiconductors [3]. In the presentation, after discussing the principle of LEIPS, the recent advances of this technique will be reported. [1] Yoshida, Chem. Phys. Lett. 539-540, 180 (2012); Yoshida, J. Electron Spectrosc. Relat. Phenom. 204, 116 (2015). [2] Yoshida, Yoshizaki, Org. Electron., 20, 24 (2015); Yoshida, J. Phys. Chem. C, 119, 24459 (2015); Yoshida, J. Phys. Chem. C, 118, 24377 (2014). [3] Zhong, et al, J. Phys. Chem. C, 119, 23-28 (2015); H. Yoshida, et al., Phys. Rev. B, 92, 075145 (2015); K. Yamada, et al., Phys. Rev. B (accepted).

Summary:

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Speaker Sessions and Seminars / 78

Nano- and microfabrication technologies for photovoltaic and supercapacitor device applications

Jae Su Yu1

1 Kyung Hee University

Corresponding Author(s): [email protected]

Over the last decades, nano- and microfabrication technologies of semiconductors have received considerable attraction for energy and optoelectronic device applications. Various fabrication techniques such as thermal dewetting, anodization, laser interference lithography, etc., followed bydry etching as well as glancing angle deposition and material growth/synthesis have been employed to create the nano- and microstructures. The fabrication technologies were developed to make some- thing better and cheaper for facile scale-up process, which is easily adaptable to industrial applications. The nano- and microstructures are formed by a combination of several fabrication technologies. Their size and height can be controlled by changing the process parameters. Recently, energy- harvesting devices including different types of solar cells for a sustainable energy source as wellas sensing devices such biosensors and photodetectors are very important in the fourth industrial revolution. For use of solar cells, coverglass is typically used during the packaging process. The light trapping in packaged solar cells should be enhanced over a wide wavelength range by overcoming some limitations. Still, the design of the structures and the device performance improvement are required. In this talk, we present the formation of nano- and microstructures of metal oxides (ZnO, TiO2, etc.) by different fabrication techniques including glancing angle deposition and thermal dewetting processes, and the structural and optical characteristics are analyzed. The fabricated structures are applied to photovoltaic and sensing devices to improve the device performance.

Summary:

Poster Session B / 10

Energy-Sensitive Ion- and Cathode-Luminescent Radiation-Beam Monitors Based on Multilayer Thin-Film Design

Author(s): Francisco Yubero1

Co-author(s): Jorge Gil-Rostra 1 ; F.J. Ferrer 2 ; Agustin R. González-Elipe 1

1 ICMS, CSIC 2 CNA, US

Corresponding Author(s): [email protected]

A multilayer luminescent design concept is presented to develop energy sensitive radiation-beam monitors on the basis of colorimetric analysis. Each luminescent layer within the stack consists of rare-earth-doped transparent oxides of optical quality and a characteristic luminescent emission under excitation with electron or ion beams. For a given type of particle beam (electron, protons, α particles, etc.), its penetration depth and therefore its energy loss at a particular buried layer within the multilayer stack depend on the energy of the initial beam. The intensity of the luminescent response of each layer is proportional to the energy deposited by the radiation beam within the layer, so characteristic colour emission will be achieved if different phosphors are considered in the layers of the luminescent stack. Phosphor doping, emission efficiency, layer thickness, and multilayer structure design are key parameters relevant to achieving a broad colorimetric response. Two case examples are designed and fabricated to illustrate the capabilities of these new types of detector to evaluate the kinetic energy of either electron beams of a few kilo-electron volts or α particles of a few mega-electron volts[1,2].

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[1] J. Gil-Rostra, F.J. Ferrer, J.P. Espinós, A.R. González-Elipe, F. Yubero, ACS Applied Materials and Interfaces 9, 16313 (2017). http://dx.doi.org/10.1021/acsami.7b01175 [2] F.J. Ferrer, J. Gil-Rostra, A.R. González-Elipe, F. Yubero, Sensors and Actuators A: Physical 272, 217 (2018). https://doi.org/10.1016/j.sna.2018.01.062

Summary:

Speaker Sessions and Seminars / 28

Dye Giant Absorption and Light Confinement Effects in Porous Bragg Microcavities

Author(s): Francisco Yubero1 Co-author(s): Manuel Oliva-Ramirez 1 ; Agustin R. Gonzalez-Elipe 1

1 ICMS, CSIC

Corresponding Author(s): [email protected]

This work presents a simple experimental procedure to probe light confinement effects inphotonic structures. Two types of porous 1D Bragg microcavities with two resonant peaks in the reflection gap were prepared by physical vapor deposition at oblique angle configurations and then infiltrated with dye solutions of increasing concentrations. The unusual position shift and intensity drop of the transmitted resonant peak observed when it was scanned through the dye absorption band have been accounted for by the effect of the light trapped at their optical defect layer.An experimentally observed giant absorption of the dye molecules and a strong anomalous dispersion in the refractive index of the solution are claimed as the reasons for the observed variations in the microcavity resonant feature. Determining the giant absorption of infiltrated dye solutions is proposed as a general and simple methodology to experimentally assess light trapping effects in porous photonic structures

Summary:

Speaker Sessions and Seminars / 253

Highlights of the IUVSTA Thin Film Division 2018

Francisco Yubero1 ; Diederik Depla2

1 ICMS (CSIC, Univ. Seville) 2 Department of Solid State Sciences, Ghent University,

Corresponding Author(s): [email protected], [email protected]

Science and technology of thin films is in continuous progress. Interesting technological approaches and initiatives for accelerated materials discovery using machine learning are under development to meet the current trends of automation and data exchange in manufacturing technologies within what is called Industry 4.0 that involves cyber-physical systems, the Internet of things, or cognitive computing. In this context, it is of paramount importance not only the development of new materials with new or improved properties, but also the search of new smart sensors and self-reporting materials able to “communicate” in service general changes in their environment or even, report on possible damage/degradation by means of the variation of their chemical or structural properties. In this presentation, we will review few selected papers that focus on either fundamental aspects related to the control of thin film growth or to their innovative application as functional coatings to meet these challenges. Thus, it will be reported how the presence of residual gases during magnetron sputtering thin film growth can be used to control the microstructure of the deposits [1]of

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importance in industrial implementation, a clever way to study elemental diffusion in bimetallic systems [2], or the conditions to grow vertically aligned columnar nanocomposite thin films [3]. Other topics that will be addressed are the fabrication of thin films by agglomeration of nanoparticles [4] to control wetting properties of these films, or the identification of ultrathin magnetic structures [5]. On the other hand, several examples of functional coatings, such as the performance of transition metal dichalcogenides/ferroelectric systems as resistive switching for resistive random access memories [6], colorimetric energy sensitive scintillators based on luminescent multilayer designs or microfluidic liquid sensors based on porous films [7] [1] F. G. Cougnon et al. Appl. Phys. Lett. 112, 221903 (2018). [2] V. Takats et al. Appl. Surf. Sci. 440, 275 (2018). [3] Y. Wang et al. Sci. Reports 7, 11122 (2017). [4] A. Shelemin et al. J. Phys. D: Appl. Phys. 49, 254001 (2016). [5] S. Ruiz-Gomez et al. Nanoscale 10, 5566 (2018). [6] J.P.B. Silva et al. J. Mat. Chem. C 5, 10353 (2017). [7] J. Gil-Rostra et al. ACS Appl. Mater. Interfaces 9, 16313 (2017). M. Oliva-Ramírez et al. Sens. Actuators B 256, 590 (2018).

Summary:

Speaker Sessions and Seminars / 139

Modifying the magnetic reversal mechanism of an exchange biased partially oxides MnxOy/Ni80Fe20 bilayer through oxygen ion implantation

Author(s): Ji Zhang1 ; Grace Causer2 Co-author(s): Frank Klose 3 ; Mihail Ionescu 4 ; Sean Li 1

1 UNSW 2 Australian Centre for Neutron Scattering 3 Guangdong Technion-Israel Institute of Technology 4 ANSTO

Corresponding Author(s): [email protected], [email protected], [email protected], [email protected]

Thin film sample Si(001)//SiO2/Ni80Fe20/MnxOy were ion sputtered. These sputtered sampleswere oxygen implanted using 8 keV ions at fluences of 1016, 1017 and 1018 ions/cm2 in order to modify the exchange bias effect at the MnxOy/Ni80Fe20 interface. The magnetic, crystallographic and chemical properties of the sample were studied before and after the implantations using transmission electron microscopy, X-ray reflectometry, magnetometry and polarised neutron reflectometry. The results show an overall improved exchange bias and coercivity of the ion implanted samples. We observed a drastic magnetic and composition phase transition of MnxOy as a function of ion fluence. The 1017 ions/cm2 implanted sample showed the highest improvement in exchange bias field and was therefore selected for studying its detailed spin reversal behaviour using polarised neutron reflectometry before and after implantation. The results reveal a coexistence of coherent and non-coherent magnetic spin reversal in the as-grown sample and a solely coherent spin rotation reversal mechanism for the implanted sample.

Summary:

Speaker Sessions and Seminars / 44

Tuning the Electronic Structure of NiO by Li doping for Electro- catalytic Water Oxidation

Gaoliang FuNone ; Kelvin H.L. Zhang1

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1 Xiamen University

Corresponding Author(s): [email protected]

Earth-abundant transition metal (TM) oxides are excellent materials as electrocatalysts for oxygen evolution reaction (OER). It has been proposed that similar to the d-band theory in metal catalysts, the intrinsic OER activity of TM oxides is strongly linked with their electronic structures, i.e., transition metal cations with an occupation of eg=1 showing a high OER activity. This provides guideline for rational design of electrocatalysts.1 We have synthesized Li doped NiO (LixNi1-xO, x= 0, 0.09, 0.17, 0.33 and 0.5) powders and found the materials show increasing catalytic activity for OER as x increases, with comparable OER activity to that of precious IrO2 when x=0.5. The dependence of structure and electronic properties on composition were systematically investigated using high- resolution X-ray photoemission spectroscopy (XPS) and X-ray absorption (XAS) at synchrotron, and density functional theory (DFT) calculations. NiO is a wide bandgap (Eg=3.6 eV) semiconductor with a nominal charge state of Ni2+ (eg2), while Ni in the other end member Li0.5Ni0.5O has a nominal charge state of Ni3+ (eg1). O-K edge XAS indicates development of unoccupied states at 0.5 eV above the top of valence band (VB) with increasing Li doping. These experimental results supplemented with DFT calculations established a direct correlation between the enhancement of catalytic activity with the change of electronic structure. [1] J. Suntivich, K. J. May, H. A. Gasteiger, J. B. Goodenough and Y. Shao-Horn, Science 334 (6061), 1383-1385 (2011).

Summary:

Speaker Sessions and Seminars / 38

Defects physics in emergent 2D material SnSe with binary black phosphorus lattice

Author(s): Yi Zheng1

Co-author(s): Zhen Wang 1 ; Da Wei Shen 2 ; Congcong Fan 3

1 Zhejiang University 2 Shanghai Institue of Microsystem and Information Technology 3 Shanghai Institute of Microsystem and Information Technology

Corresponding Author(s): [email protected], [email protected]

In this talk, we will show the pronounced effects of various defects in determing the physical properties of the emergent 2D material SnSe with binary black phosphorus lattice. SnSe has been reported with record-breaking thermoelectric conversion efficiency very recently. However, to date a comprehensive understanding of the electronic structure and most critically, the self hole-doping mechanism in SnSe is still absent. We for the first time fully unfold the highly anisotropic electronic structure of SnSe by angle-resolved photoemission spectroscopy, which reveals a unique pudding- mould-shaped valence band with quasi-linear energy dispersion. We prove that p-type doping in SnSe is extrinsically controlled by local phase segregation of SnSe2 microdomains via interfacial charge transferring. The multivalley nature of the pudding-mould band is manifested in quantum transport by crystallographic axis-dependent weak localisation and exotic non-saturating negative magnetoresistance. Strikingly, quantum oscillations also reveal 3D Fermi surface with unusual interlayer coupling strength in p-SnSe, in which individual monolayers are interwoven by peculiar point dislocation defects. The fingerprinting pudding-mould multivalley band structure is well reserved in bismuth-doped n-type SnSe, which suggest the feasibility of an all-SnSe functioning device.

Summary:

275

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Emerging Challenges in Surface Science

Summary:

Poster Session - Main Hall Tuesday / 207

Poster Session Themes

• Electronic Materials / Processing • Magnetic surfaces, interfaces and nanostructures • Radiation Sciences and Technology • Surface Science • Thin Film • Vacuum Science and Technology

Poster Session - Main Hall Tuesday / 156

Poster Session Themes

• Applied Surface Science • Plasma Science & Technology • Biosurfaces, interfaces, nanostructures • Surface Engineering • Nanometer Scale Science & Technology • Renewable Energy Technologies

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