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2014 Spring Meeting Lille, France – May 26th - 30th SYMPOSIUM E E Defect-induced effects in nanomaterials Symposium Organizers: Flyura Djurabekova, University of Helsinki, Finland Eugene Kotomin, University of Latvia, Latvia Mark C. Ridgway, Australian National University, Australia Nikolai A. Sobolev, Universidade de Aveiro and I3N, Portugal Published in Physica Status Solidi C EMRS - Strasbourg Page 1 of 29 PROGRAM VIEW : 2014 Spring MY PROGRAM : 2014 Spring Symposium : E Defect-induced effects in nanomaterials 26 May 2014 27 May 2014 28 May 2014 29 May 2014 30 May 2014 hide a start at Subject Num. Properties of graphene : Arkady Krasheninnikov 09:00 Defects in two-dimensional materials and nanoparticles -- Theory and microscopy Authors : Sokrates T. Pantelides, Stephen J. Pennycook Affiliations : Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA and Oak Ridge National Laboratory, Oak Ridge, TN USA; University of Tennessee, Knoxville, TN USA Resume : Calculations based on density functional theory using high- performance computers have made enormous strides in describing the atomic- scale properties of complex materials. In parallel, aberration-corrected scanning transmission electron microscopy has reached extraordinary levels of spatial and energy resolution, in both imaging and electron-energy-loss spectroscopy. The combination of theory and microscopy provides an unparalleled probe of the atomic-scale structure, properties, and dynamics of complex systems, especially defects, boundaries, interfaces and nanoparticles. Here we describe recent results on defects in graphene, MoS2 monolayers, and CuInS2 nanoparticles. EO1 More specifically, we will discuss plasmon enhancement at Si impurities in 1 graphene [1], Si6 clusters and Si-passivated nanovoids in graphene [2], nanowire formation in MoS2 monolayers [3], and a unique form of crystalline order observed in CuInS2 nanoparticles [4]. Primary collaborators: Theory: Jaekwang Lee, Xiao Shen, Junhao Lin; microscopy: Wu Zhou, Juan C. Idrobo, Junhao Lin, Matt Chisholm; This work was supported by the US Department of Energy Basic Energy Sciences, Materials Science and Engineering directorate. 1. W. Zhou et al., “Atomically localized plasmon enhancement in monolayer graphene”, Nature Nanotechn. 7, 161 (2012). 2. J. Lee et al., Direct visualization of reversible dynamics in a Si6 cluster embedded in a graphene pore, Nature Commun. 4, 1650 (2013); J. Lee et al. “Stabilizaion of graphene nanopores”, under review. 3. J. Lin et al., “Flexible metallic nanowires with self- adaptive contacts to semiconducting transition-metal dichalcogenide monolayers”, under review. 4. X. Shen et al., “Interlaced crystals: ‘Perfect Bravais lattices with interlaced chemical order revealed by real-space crystallography”, under review. add to my program (close full abstract) 09:30 Scanning Probe Microscopy Characterization of Grain Boundaries in CVD Graphene and Nanolithography Authors : L. P. Biró1, 4, L. Tapasztó1, 4, G. Magda1, 4, P. Nemes-Incze1, 4, G. Dobrik1, 4, P. Vancsó1, 4, Z. Osváth 1, 4, G. I. Márk1, 4, Ph. Lambin2, X. Jin3, 4, Y. S. Kim3, 4, C. Hwang3, 4 Affiliations : 1Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, 1525 Budapest, PO Box 49, Hungary, http://www.nanotechnology.hu/; 2Department of Physics of Matter and Radiations, University of Namur (FUNDP), 61 Rue EO1 de Bruxelles, B-5000 Namur, Belgium; 3Center for Nano-metrology Division of Industrial 2 Metrology Korea Research Institute of Standards and Science, 267 Gaejeong-ro, Yuseong -Gu, Daejeon 305-340, Republic of Korea; 4Korean-Hungarian Joint Laboratory for Nanosciences (KHJLN), P.O. Box 49, 1525 Budapest, Hungary Resume : Graphene is an excellent candidate to replace silicon in nanoelectronics, to mention only the most exciting from its many potential applications [1]. Chemical Vapor Deposition (CVD) is the industrially most viable way of producing large area graphene layers [2]. The CVD graphene is http://www.emrs-strasbourg.com/index.php?option=com_abstract&task=view&id=240&y... 06/05/2014 EMRS - Strasbourg Page 2 of 29 polycrystalline [3], therefore the characterization of the grain structure and the effect of individual grain boundaries (GBs) is a must, if any serious practical application is intended. AFM [4], and STM [5, 6] in combination with numerical simulations [7] are extremely useful in understanding the structure and electronic properties of the GBs in CVD graphene. Furthermore, STM is very well suited for the nanolithography of the material with nanometer precision and full crystallographic orientation control of the edges of the nanoarchitectures. [1] Novoselov, K. Rev. Mod. Phys. 83, 837–849 (2011). [2] Bae, S. et al. Nat. Nanotechnol. 5, 574–578 (2010). [3] Biró, L. P. & Lambin, P. New J. Phys. 15, 035024 (2013). [4] Nemes-Incze, P. et al. Appl. Phys. Lett. 99, 023104–1– 023104–3 (2011). [5] Tapasztó, L. et al. Appl. Phys. Lett. 100, 053114 (2012). [6] Nemes-Incze, P. et al. Carbon N. Y. 64, 178–186 (2013). [7] Vancsó, P., et al., Carbon N. Y. 64, 101–110 (2013). add to my program (close full abstract) 09:45 Dirac-states in a Ta-doped TiO2 nanowire: basis for a new type of high-speed field effect transistors. Authors : Peter Deák,1 Bálint Aradi,1 Alessio Gagliardi,1,2 Huynh Anh Huy,1 Gabriele Penazzi,1 Binghai Yan,1 Tim Wehling,1,3 and Thomas Frauenheim1 Affiliations : 1 Bremen Center for Comp. Mater. Sci., University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany; 2 Department of Electronic Engineering, University of Rome “Tor Vergata”, via del Politecnico 1, I-00133 Roma, Italy; 3 Institute for Theoretical Physics, University of Bremen, Otto-Hahn-Allee 1, D-28359 Bremen, Germany Resume : Dirac-states in graphene nanoribbons or topological insulators have very high mobility, but the lack of a sizeable gap results in electronic switching devices with a much too low on-off ratio [1]. Based on theoretical calculations, we have discovered [2], that [001] nanowires of anatase-TiO2 posses Dirac- states near the wide fundamental band gap, just above the conduction band EO1 edge. A gate voltage could shift the Fermi-level into the Dirac-region, switching 3 the system between the “classical” high-resistivity semiconducting and a relativistic high-mobility metallic range. The band gap of an anatase-TiO2 nanowire is too wide, to tune the Fermi-level from its intrinsic position at midgap above the conduction band edge. Therefore, n-type doping is necessary. Here we present computational studies on Nb- and Ta-doping of anatase [001] nanowires. We show, that the solubility is good and the dopants prefer high symmetry sites inside the wires. We also show that Ta does not destroy the Dirac-states, and a random distribution does not give rise to Anderson localization either. [1] F. Schwierz, Graphene transistors. Nat. Nanotechnol. 5, 487 (2010). [2] Deák, B Aradi, A. Gagliardi, H. A. Huy, G. Penazzi, B. Yan, T. Wehling, and T. Frauenheim, Possibility of a Field Effect Transistor Based on Dirac Particles in Semiconducting Anatase-TiO2 Nanowires. Nanoletters, 13, 1073-1079 (2013). add to my program (close full abstract) 10:00 Break Two-dimensional materials : Sokrates Pantelides 10:30 Native and irradiation-induced defects in two-dimensional materials Authors : Arkady V. Krasheninnikov Affiliations : Department of Applied Physics, Aalto University, Finland Resume : Following the isolation of a single sheet of graphene, many other 2D systems such as h-BN, transition metal dichalcogenides (TMD), and SiO2 sheets were later manufactured. All these materials have native defects, which naturally affect their properties. Moreover, defects can deliberately be introduced by ion and electron irradiation to tailor the properties of 2D materials. In my talk, I will summarize our knowledge about defects [1,2] in EO2 graphene and other 2D systems. I will also touch upon defect production in 2D 1 systems under impacts of energetic ions and electrons and present theoretical data obtained in collaboration with several experimental groups [3-6]. I will also dwell upon impurity and defect-mediated engineering of the electronic structure of 2D materials such as BN or TMDs. I will finally touch upon defects in bilayer 2D silica [8] and show that point and line defects in this system are strikingly similar to those in graphene with their morphology being governed by the hexagonal symmetry of the lattice. 1. F. Banhart, et al. ACS Nano, 5 (2011) 26. 2. O. Lehtinen et al. Nature Comm. 4 (2013) 2098. 3. M. Kalbac, et al. Adv. Mat. 25 (2013) 1004. 4. J. Meyer, et al. PRL 108 (2012) 196102. 5. H.-P. http://www.emrs-strasbourg.com/index.php?option=com_abstract&task=view&id=240&y... 06/05/2014 EMRS - Strasbourg Page 3 of 29 Komsa, et al. PRL 109 (2012) 035503; PRB 88 (2013) 035301. 6. R. R. Nair, et al. Nature Comm. 4 (2013) 2010. 7. Y. Lin et al. Adv. Mat. (2014) accepted. 8. T. Björkman et al. Sci. Rep. 3 (2013) 3482. add to my program (close full abstract) 11:00 Excitons and stacking order in h-BN Authors : A. Zobelli, R. Bourellier, M. Amato, L.H.G. Tizei, C. Giorgetti, A. Gloter, M.I. Heggie, K. March, O. Stephan, L. Reining, M. Kociak Affiliations : Laboratoire de Physique des Solides, Univ. Paris-Sud, CNRS UMR 8502, F- 91405, Orsay, France; Laboratoire des Solides Irradies, Ecole Polytechnique, Route de Saclay, F-91128 Palaiseau and European Theoretical Spectroscopy Facility (ETSF), France; Department of Chemistry, University of Surrey, Guildford GU2 7XH, United Kingdom Resume : The strong excitonic emission of hexagonal boron nitride (h-BN) makes this material one of the most promising candidate for light emitting devices in the far ultraviolet (UV). However, single excitons occur only in perfect EO2 monocrystals that are extremely hard to synthesize, while regular h-BN samples 2 present a complex emission spectrum with several additional peaks. Despite a large number of experimental and theoretical studies, the microscopic origin of these additional emissions has not yet been understood.