DOCSLIB.ORG

Synthesis, Characterization, and Fabrication of Boron Nitride and Carbon Nanomaterials, Their Applications, and the Extended

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Synthesis, Characterization, and Fabrication of Boron Nitride and Carbon Nanomaterials, Their Applications, and the Extended Synthesis, Characterization, and Fabrication of Boron Nitride and Carbon Nanomaterials, their Applications, and the Extended Pressure Inductively Coupled Plasma Synthesis of Boron Nitride Nanotubes by Aidin Fathalizadeh A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Physics in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Alex K. Zettl, Chair Professor Michael F. Crommie Professor Liwei Lin Spring 2016 Synthesis, Characterization, and Fabrication of Boron Nitride and Carbon Nanomaterials, their Applications, and the Extended Pressure Inductively Coupled Plasma Synthesis of Boron Nitride Nanotubes Copyright 2016 by Aidin Fathalizadeh 1 Abstract Synthesis, Characterization, and Fabrication of Boron Nitride and Carbon Nanomaterials, their Applications, and the Extended Pressure Inductively Coupled Plasma Synthesis of Boron Nitride Nanotubes by Aidin Fathalizadeh Doctor of Philosophy in Physics University of California, Berkeley Professor Alex K. Zettl, Chair Nanoscale materials made of carbon, boron, and nitrogen, namely BCN nanostructures, exhibit many remarkable properties making them uniquely suitable for a host of applications. Boron nitride (BN) and carbon (C) nanomaterials are structurally similar. The forms studied here originate from a two-dimensional hexagonally arranged structure of sp2 bonded atoms. These nanomaterials exhibit extraordinary mechanical and thermal properties. However, the unique chemical compositions of carbon and boron nitride result in differing electrical, chemical, biological, and optical properties. In this work, we explore the single layer sheets of sp2 bonded carbon (graphene), and their cylindrical forms (nanotubes) of carbon and boron nitride. In the first part of this work, we look at carbon based nanomaterials. In Chapter 2, the electron field emission properties of carbon nanotubes (CNTs) and their implementation as nanoelectromechanical oscillators in an integrated device will be discussed. We show a technique hereby a single CNT is attached to a probe tip and its electron field emission characterized. We then delve into the fabrication of a field emitting CNT oscillator based integrated device using a silicon nitride membrane support. We then present the electron field emission capabilities of these devices and discuss their potential use for detection of nuclear magnetic resonance (NMR) signals. Graphene is the subject of study in Chapter 3. We begin by extensively examining the synthesis of graphene using a chemical vapor deposition (CVD) process, ultimately establishing techniques to control graphene domain size, shape, and number of layers. We then discuss the application of the single-atom thick, but ultra-mechanically strong graphene as a capping layer to trap solutions in a custom fabricated silicon nitride membrane to enable transmission electron microscopy (TEM) of liquid environments. In this manner, the volume and position of liquid cells 2 for electron microscopy can be precisely controlled and enable atomic resolution of encapsulated particles. In the second portion of this work, we investigate boron nitride nanostructures and in particular nanotubes. In Chapter 4, we present the successful development and operation of a high-throughput, scalable BN nanostructures synthesis process whereby precursor materials are directly and continuously injected into a novel high- temperature, Extended-Pressure Inductively-Coupled plasma system (EPIC). The system can be operated in a near-continuous fashion and has a record output of over 35 g/hour for pure, highly crystalline boron nitride nanotubes (BNNTs). We also report the results of numerous runs exploring the wide range of operating parameters capable with the EPIC system. In Chapter 5, we examine the impurities present in as-synthesized BNNT materials. Several methods of sample purification are then investigated. These include chemical oxidation, using both gas and liquid phase based methods, as well as physical separation techniques. The large scale synthesis of BNNTs has opened the door for further studies and applications. In Chapter 6, we report a novel wet-chemistry based route to fill in the inner cores of BNNTs with metals. For the first time, various metals are loaded inside of BNNTs, forming a plethora of structures (such as rods, short nanocrystals, and nanowires), using a solution-based method. We are also able to initiate and observe dynamics of the metallic nanoparticles, including their movement, splitting, and fusing, within a BNNT. i To and آ ات آ ان ii Contents Table of Contents ................................................................................................. ii List of Figures ..................................................................................................... vii Chapter 1 Introduction.. ....................................................................................................... 1 1.1 Carbon ..............................................................................................................1 1.1.1 sp3 Hybridization ..................................................................................2 1.1.2 sp2 Hybridization ..................................................................................2 1.1.3 sp Hybridization ....................................................................................3 1.1.4 C60 .........................................................................................................3 1.1.5 Carbon Nanotubes ................................................................................4 1.2 Boron Nitride ....................................................................................................6 1.2.1 sp3 Hybridization ..................................................................................7 1.2.2 sp2 Hybridization ..................................................................................7 1.2.3 Boron Nitride Nanotubes .....................................................................8 1.3 Nanotube Properties ......................................................................................10 1.3.1 Electronic ............................................................................................10 1.3.2 Piezoelectricity ...................................................................................11 1.3.3 Electron Field Emission .......................................................................11 1.3.4 Optical .................................................................................................12 1.3.5 Mechanical .........................................................................................12 1.3.6 Thermal ...............................................................................................12 1.4 BxCyNz Materials ............................................................................................13 Chapter 2 Carbon Nanotubes: Field Emission and CNT Integrated Device Fabrication .......... 14 2.1 CNT Electromechanical Systems ....................................................................14 iii 2.2 Electron Field Emission ...................................................................................15 2.3 CNT-Tipped Probes .........................................................................................17 2.3.1 Fabrication ..........................................................................................17 2.3.2 Field Emission Characterization .........................................................20 2.3.3 CNT-SPM Field Emission Improvement ..............................................24 2.4 CNT Integrated Devices ..................................................................................26 2.4.1 Fabrication ..........................................................................................27 2.4.2 Electrical Biasing of Devices ...............................................................32 2.4.3 Field Emission Characterization .........................................................35 2.5 CNT NEMS Devices .........................................................................................38 2.6 Nano-antennae for NMR Signal Detection .....................................................39 2.6.1 Nuclear Magnetic Resonance .............................................................39 2.6.2 NMR Resonance Techniques ..............................................................40 2.6.3 CNT-Based NMR Signal Detection ......................................................41 Chapter 3 Graphene: CVD Synthesis and Fabrication of Next-Generation Graphene Liquid Cells ......................................................................................... 47 3.1 Graphene ........................................................................................................47 3.1.1 Structure and Properties ....................................................................47 3.2 Graphene Synthesis ........................................................................................48 3.2.1 Chemical Vapor Deposition ................................................................49 3.2.2 Large Domain Graphene Synthesis ....................................................51 3.2.3 Growth Mechanism ............................................................................76 3.2.4 Multilayer vs. Monolayer Growth ......................................................77 3.3
Load more

Recommended publications
  • Boron Nitride Substrates for High-Quality Graphene Electronics C
    LETTERS PUBLISHED ONLINE: 22 AUGUST 2010 | DOI: 10.1038/NNANO.2010.172 Boron nitride substrates for high-quality graphene electronics C. R. Dean1,2*,A.F.Young3,I.Meric1,C.Lee4,5,L.Wang2,S.Sorgenfrei1,K.Watanabe6,T.Taniguchi6, P. Kim 3,K.L.Shepard1 and J. Hone2* Graphene devices on standard SiO2 substrates are highly disor- atomically planar surface should suppress rippling in graphene, dered, exhibiting characteristics that are far inferior to the which has been shown to mechanically conform to both corrugated expected intrinsic properties of graphene1–12. Although suspend- and flat substrates9,21. The dielectric properties of h-BN (e ≈ 3–4 ≈ 21 ing the graphene above the substrate leads to a substantial and Vbreakdown 0.7 V nm ) compare favourably with those of 13,14 improvement in device quality ,thisgeometryimposes SiO2, allowing the use of h-BN as an alternative gate dielectric with severe limitations on device architecture and functionality. no loss of functionality22. Moreover, the surface optical phonon There is a growing need, therefore, to identify dielectrics that modes of h-BN have energies two times larger than similar modes allow a substrate-supported geometry while retaining the in SiO2, suggesting the possibility of an improved high-temperature quality achieved with a suspended sample. Hexagonal boron and high-electric-field performance of h-BN based graphene devices nitride (h-BN) is an appealing substrate, because it has an atom- over those using typical oxide/ graphene stacks23,24. ically smooth surface that is relatively free of dangling bonds and To fabricate graphene-on-BN, we used a mechanical transfer charge traps.
    [Show full text]
  • Optimization of Wear Loss in Silicon Nitride (Si3n4)–Hexagonal Boron Nitride (Hbn) Composite Using Doe–Taguchi Method
    Ghalme et al. SpringerPlus (2016) 5:1671 DOI 10.1186/s40064-016-3379-7 CASE STUDY Open Access Optimization of wear loss in silicon nitride (Si3N4)–hexagonal boron nitride (hBN) composite using DoE–Taguchi method Sachin Ghalme1,2*, Ankush Mankar3 and Y. J. Bhalerao4 *Correspondence: [email protected] Abstract 2 Mechanical Engineering Introduction: The contacting surfaces subjected to progressive loss of material Department, Manoharbhai Patel Institute of Engineering known as ‘wear,’ which is unavoidable between contacting surfaces. Similar kind of and Technology, Gondia, phenomenon observed in the human body in various joints where sliding/rolling Maharashtra, India contact takes place in contacting parts, leading to loss of material. This is a serious issue Full list of author information is available at the end of the related to replaced joint or artificial joint. article Case description: Out of the various material combinations proposed for artificial joint or joint replacement Si3N4 against Al2O3 is one of in ceramic on ceramic category. Minimizing the wear loss of Si3N4 is a prime requirement to avoid aseptic loosening of artificial joint and extending life of joint. Discussion and evaluation: In this paper, an attempt has been made to investigate the wear loss behavior of Si3N4–hBN composite and evaluate the effect of hBN addition in Si3N4 to minimize the wear loss. DoE–Taguchi technique is used to plan and analyze experiments. Conclusion: Analysis of experimental results proposes 15 N load and 8 % of hBN addi- tion in Si3N4 is optimum to minimize wear loss against alumina. Keywords: Silicon nitride (Si3N4), Hexagonal boron nitride (hBN), Alumina (Al2O3), Design of experiment (DoE), Taguchi technique Background Mechanical behavior of various machine elements, such as gears, cams, wheels, rails and sealing parts are influenced by the interaction between contact elements and surfaces.
    [Show full text]
  • Ceramic Carbides: the Tough Guys of the Materials World
    Ceramic Carbides: The Tough Guys of the Materials World by Paul Everitt and Ian Doggett, Technical Specialists, Goodfellow Ceramic and Glass Division c/o Goodfellow Corporation, Coraopolis, Pa. Silicon carbide (SiC) and boron carbide (B4C) are among the world’s hardest known materials and are used in a variety of demanding industrial applications, from blasting-equipment nozzles to space-based mirrors. But there is more to these “tough guys” of the materials world than hardness alone—these two ceramic carbides have a profile of properties that are valued in a wide range of applications and are worthy of consideration for new research and product design projects. Silicon Carbide Use of this high-density, high-strength material has evolved from mainly high-temperature applications to a host of engineering applications. Silicon carbide is characterized by: • High thermal conductivity • Low thermal expansion coefficient • Outstanding thermal shock resistance • Extreme hardness FIGURE 1: • Semiconductor properties Typical properties of silicon carbide • A refractive index greater than diamond (hot-pressed sheet) Chemical Resistance Although many people are familiar with the Acids, concentrated Good Acids, dilute Good general attributes of this advanced ceramic Alkalis Good-Poor (see Figure 1), an important and frequently Halogens Good-Poor overlooked consideration is that the properties Metals Fair of silicon carbide can be altered by varying the Electrical Properties final compaction method. These alterations can Dielectric constant 40 provide knowledgeable engineers with small Volume resistivity at 25°C (Ohm-cm) 103-105 adjustments in performance that can potentially make a significant difference in the functionality Mechanical Properties of a finished component.
    [Show full text]
  • Crystal Structure of Hexabarium Mononitride Pentaindide,(Ba6n)[In5]
    Z. Kristallogr. NCS 219 (2004) 349-350 349 © by Oldenbourg Wissenschaftsverlag, München Crystal structure of hexabarium mononitride pentaindide, (Ba6N)[In5] A. Schlechte, Yu. Prots and R. Niewa* Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, 01187 Dresden, Germany Received October 1, 2004, accepted and available on-line November 12, 2004; CSD no. 409805 Discussion Indium, when combined with alkaline-earth elements forms a va- riety of ternary nitrides. The compounds known so far may be de- scribed as built from indium clusters and octahedra of alkaline- earth cations surrounding nitride ions. In the latter cationic sub- structure the polyhedra might be isolated, vertex-, and/or edge- sharing. The variety of In arrangements extends from isolated In species in (Ca7N4)Ini.o4 [1], isolated tetrahedral units in (AI9N7)[ID4]2 (A = Ca, Sr, Ba) [2,3], trigonal bipyramidal [Ins] clusters next to [Ins] ions of more complicated geometry in (Ba38Ni8)[In5]2[In8] [4], and infinite chains in (A4N)[In2] (A = Ca, Sr) [5] and (Ca2N)In [6]. None of these metallic compounds follows Zintl-like counting. The new compound (Ba6N)[Ins] is an isotype of (¿6N)[Ga5] (A = Sr, Ba) [7]. The crystal structure of (Ba6N)tIns] is characterized as rocksalt type motif of N-centred octahedra (BaiN) and trigonal bi- pyramidal clusters [Ins]. The trigonal bipyramidal units [Ins] might be described as [Ins]7- ions, quite the same according to Zintl-type electronic counting and using the Wade-rules for closo-cluster. The isotypes (AeN)[Gas] were previously de- scribed by the formula (A2+)6(N3-)[Ga5]7~ • 2e_ based on elec- tronic structure calculations.
    [Show full text]
  • High-Quality Graphene and Hexagonal- Boron Nitride Transfers on Sio2
    High-Quality Graphene and Hexagonal- Boron Nitride Transfers on SiO2 1 MELISSA HUYNH CHEMICAL ENGINEERING DEPARTMENT OF OREGON STATE UNIVERSITY DR. JUN JIAO, LESTER LAMPERT REU - PORTLAND STATE UNIVERSITY Overview 2 Importance High- Results and Quality Methodology Interpretation Graphene & HBN Raman Analysis Overview 3 Importance High- Results and Quality Methodology Interpretation Graphene & HBN Raman Analysis 2D Materials 4 Graphene Zero overlap semimetal Durable Heat and electricity conductivity Hexagonal-Boron Nitride Similar properties to graphene Future Application 5 Biological engineering Optical Electronics Composite materials Super Capacitors/ Energy Storage Overview 6 Importance High- Results and Quality Methodology Interpretation Graphene & HBN Raman Analysis Growth 7 Chemical Vapor Deposition (CVD) Copper catalyst Vertical growth with furnace Methane, hydrogen, argon gases Transfer of Graphene 8 PMMA spin coat Ammonium Persulfate (APS) Rinse Heat Acetone bath Transfer of HBN 9 Copper foil APS Corral Pumps Polymer-Free Approach 10 Similar to H-BN Outflow: APS Inflow: DI H2O and Isopropyl Alcohol Overview 11 Importance High- Results and Quality Methodology Interpretation Graphene & HBN Raman Analysis Graphene Spectrum 12 D band G band D/g 2D Band 2D/G Ideal Spectrum HBN spectrum 13 1300-1400 range Weak readings Carbon contamination Ideal Spectrum Overview 14 Importance High- Results and Quality Methodology Interpretation Graphene & HBN Raman Analysis Graphene Analysis Grown at 830 ̊ C [edge]
    [Show full text]
  • Production of Boron Nitride Using Chemical Vapor Deposition Method a Thesis Submitted to the Graduate School of Nature
    PRODUCTION OF BORON NITRIDE USING CHEMICAL VAPOR DEPOSITION METHOD A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURE AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY ÖZGE MERCAN IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN CHEMICAL ENGINEERING FEBRUARY 2014 Approval of the thesis: PRODUCTION OF BORON NITRIDE USING CHEMICAL VAPOR DEPOSITION METHOD submitted by ÖZGE MERCAN in partial fulfillment of the requirements for the degree of Master of Science in Chemical Engineering Department, Middle East Technical University by, Prof. Dr. Canan Özgen Dean, Graduate School of Natural and Applied Sciences Prof. Dr. Halil Kalıpçılar Head of Department, Chemical Engineering, Prof. Dr. H. Önder Özbelge Supervisor, Chemical Engineering Dept, Assoc. Prof. Dr. Naime Aslı Sezgi Co-supervisor, Chemical Engineering Dept, Examining Committee Members Prof. Dr. Hayrettin Yücel Chemical Engineering Department, METU Prof. Dr. H. Önder Özbelge Chemical Engineering Department, METU Prof. Dr. Nail Yaşyerli Chemical Engineering Department, Gazi Unv. Prof. Dr. Halil Kalıpçılar Chemical Engineering Department, METU Yard. Doç. Dr. Zeynep Çulfaz Emecen Chemical Engineering Department, METU Date : I hereby declare that all information in this document has been obtained and presented in accordance with academic rules, and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last Name : ÖZGE MERCAN Signature : iv ABSTRACT PRODUCTION OF BORON NITRIDE USING CHEMICAL VAPOR DEPOSITION METHOD Mercan, Özge Master of Science, Department of Chemical Engineering Supervisor : Prof. Dr. H. Önder Özbelge Co-Supervisor: Assoc.
    [Show full text]
  • Structural and Electronic Properties of Indium Rich Nitride Nanostructures
    francesco ivaldi STRUCTURALANDELECTRONICPROPERTIESOF INDIUMRICHNITRIDENANOSTRUCTURES STRUCTURALANDELECTRONICPROPERTIESOFINDIUM RICHNITRIDENANOSTRUCTURES francesco ivaldi Institute of Physics Polish Academy of Science Laboratory of X-Ray and electron microscopy research Group of electron microscopy Promotor: Prof. nzw. dr hab. Piotr Dłuzewski˙ Warsaw, September 2015 Francesco Ivaldi: Structural and electronic properties of indium rich ni- tride nanostructures, III-V heterostructures investigated by TEM and connected methods, c September 2015 ABSTRACT New materials such as III-N ternary alloys are object of increasing interest in the field of micro- and nanotechnology due to their rel- evant optical and electronical properties. Those alloys are especially appealing to be used to form quantum nanostructures for various de- vice applications such as laser emitting diodes, high electron mobility transistors and solar cells. This thesis investigates the properties of InGaN and AlInN alloys with high indium content (> 25 %). TEM and STEM combined with EELS and EDX investigations have been used to correlate the struc- tural changes with the local electronic and optical properties of In- GaN quantum wells and InN quantum dots as a consequence of ther- mal processes. Annealing of InGaN quantum wells and capping of both InN quan- tum dots and quantum wells under different conditions have been investigated. Image processing techniques such as geometric phase analysis of HR-TEM images were used to reveal significant fluctua- tions in the indium distribution on a nanometric scale inside the wells. The growth parameters leading to improved photoemission proper- ties have been determined. MBE and MOCVD grown samples have been used to analyze the influence of the temperature of the quantum barrier growth on the structural and electronic properties of the samples.
    [Show full text]
  • Indium Nitride Growth by Metal-Organic Vapor Phase Epitaxy
    INDIUM NITRIDE GROWTH BY METAL-ORGANIC VAPOR PHASE EPITAXY By TAEWOONG KIM A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2006 Copyright 2006 by Taewoong Kim ACKNOWLEDGMENTS The author wishes first to thank his advisor, Dr. Timothy J. Anderson, for providing five years of valuable advice and guidance. Dr. Anderson always encouraged the author to approach his research from the highest scientific level. He is deeply thankful to his co-advisor, Dr. Olga Kryliouk, for her valuable guidance, sincere advice, and consistent support for the past five years. Secondly, the author wishes to thank the remaining committee members of Dr. Steve Pearton and Dr. Fan Ren for their advice and guidance The author is grateful to Scott Gapinski, the staff at Microfabritech, and Eric Lambers, the staff at the Major Analytical Instrumentation Center, especially for Auger characterization. Acknowledgement needs to be given to Sangwon Kang who worked with the author for the past year and provided valuable assistance. Thanks go to Youngsun Won for his useful discussion of quantum calculation and SEM characterization, and to Dr. Jianyun Shen for her assistance about how to use the ThermoCalc. The author wishes to thank Hyunjong Park for useful discussion and Youngseok Kim for his kindness and friendship. Most importantly, the author is grateful to Moonhee Choi, his beloved wife, for her endless support, trust, love, sacrifice and encouragement. Without her help, he would have not finished the Ph.D. course. iii The author is grateful to his mother, father, mother-in-law, father-in-law, sisters, and brother for providing love, support and guidance throughout his life.
    [Show full text]
  • Nonaqueous Syntheses of Metal Oxide and Metal Nitride Nanoparticles
    Max-Planck Institut für Kolloid and Grenzflächenforschung Nonaqueous Syntheses of Metal Oxide and Metal Nitride Nanoparticles Dissertation zur Erlangung des akademischen Grades “doctor rerum naturalium” (Dr. rer. nat.) in der Wissenschaftsdisziplin “Kolloidchemie” eingereicht an der Mathematisch-Naturwissenschaftlichen Fakultät Universität Potsdam von Jelena Buha Potsdam, im Januar 2008 Dieses Werk ist unter einem Creative Commons Lizenzvertrag lizenziert: Namensnennung - Keine kommerzielle Nutzung - Weitergabe unter gleichen Bedingungen 2.0 Deutschland Um die Lizenz anzusehen, gehen Sie bitte zu: http://creativecommons.org/licenses/by-nc-sa/2.0/de/ Elektronisch veröffentlicht auf dem Publikationsserver der Universität Potsdam: http://opus.kobv.de/ubp/volltexte/2008/1836/ urn:nbn:de:kobv:517-opus-18368 [http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18368] С’ вером у Богa Abstract Nanostructured materials are materials consisting of nanoparticulate building blocks on the scale of nanometers (i.e. 10-9 m). Composition, crystallinity and morphology can enhance or even induce new properties of the materials, which are desirable for todays and future technological applications. In this work, we have shown new strategies to synthesise metal oxide and metal nitride nanomaterials. The first part of the work deals with the study of nonaqueous synthesis of metal oxide nanoparticles. We succeeded in the synthesis of In2O3 nanopartcles where we could clearly influence the morphology by varying the type of the precursors and the solvents; of ZnO mesocrystals by using acetonitrile as a solvent; of transition metal oxides (Nb2O5, Ta2O5 and HfO2) that are particularly hard to obtain on the nanoscale and other technologically important materials. Solvothermal synthesis however is not restricted to formation of oxide materials only.
    [Show full text]
  • Supporting Information Synthesis and Morphology Evolution of Indium Nitride
    Electronic Supplementary Material (ESI) for CrystEngComm. This journal is © The Royal Society of Chemistry 2019 Supporting Information Synthesis and morphology evolution of Indium nitride (InN) nanotubes and nanobelts by chemical vapor deposition Wenqing Song, Jiawei Si, Shaoteng Wu, Zelin Hu, Lingyun Long, Tao Li, Xiang Gao, Lei Zhang, Wenhui Zhu, Liancheng Wang* State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha Hunan, 410083, China Corresponding author: Liancheng Wang: [email protected]. Contents Fig.S1, SEM images were taken from the edge of samples, Fig.S2, Cross section diagram of synthetic samples in the tube furnace Fig.S3 the growth process changes from a kinetically limited process to diffusion control mode Fig.S4 the diffusion capacity of InN molecules on the InN jagged strip Fig.S5 the diffusion rate increased with morphology variation at different temperature Fig.S6 the product of InN narrow triangular sheets grown at 710℃ and heated them to 720 and 735℃ Fig.S7 a EDS spectrum of InN nanostructure, Fig.S7 b catalyst particles or metal droplets on the top of InN NWs, Fig.S7 c fusion of nanowire to leaf membrane from surface diffusion, Fig.S7 d angle formation of two or more jagged strips connect each other In Fig.S1, SEM images are taken from the center of samples, the morphology of samples is the same for samples at the edge or center. The difference lies in the density and the length of samples. The density and the length of some InN nanostructures samples in the edge are lower and longer.
    [Show full text]
  • Getting Ready for Indium Gallium Arsenide High-Mobility Channels
    88 Conference report: VLSI Symposium Getting ready for indium gallium arsenide high-mobility channels Mike Cooke reports on the VLSI Symposium, highlighting the development of compound semiconductor channels in field-effect transistors on silicon for CMOS. esearchers across the world are readying the layer overgrowth or aspect-ratio trapping (ART) — are implementation of indium gallium arsenide free in the vertical direction, and thickness and surface R(InGaAs) and other III-V compound semicon- smoothness are determined post-growth by lithography ductors as high-mobility channel materials in field- or chemical mechanical polishing (CMP). The CELO effect transistors (FETs) on silicon (Si) for mainstream process filters out defects by the abrupt change in complementary metal-oxide-semiconductor (CMOS) growth direction from vertical to lateral, as constrained electronics applications. The latest Symposia on VLSI by the cavity. The researchers believe their technique Technology and Circuits in Kyoto, Japan in June featured avoids the main problems of alternative methods of a number of presentations from leading companies and integrating InGaAs into CMOS in terms of limited wafer university research groups directed towards this end. size, high cost, roughness, or background doping. In addition, Intel is proposing gallium nitride (GaN) The cap of the cavity was removed to access the for mobile applications such as voltage regulators or InGaAs for device fabrication. Also the InGaAs material radio-frequency power amplifiers, which require low was removed from the seed region to electrically power consumption and low-voltage operation. Away isolate the resulting devices from the underlying from III-V semiconductors, much interest has been silicon substrate.
    [Show full text]
  • LED) Materials and Challenges- a Brief Review
    6 IV April 2018 http://doi.org/10.22214/ijraset.2018.4723 International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 6.887 Volume 6 Issue IV, April 2018- Available at www.ijraset.com Different Types of in Light Emitting Diodes (LED) Materials and Challenges- A Brief Review BY Susan John1 1Dept Of Physics S. F. S College Nagpur 06, Maharashtra State. India I. INTRODUCTION LEDs are semiconductor devices, which produce light when current flows through them. It is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated. When a suitable current is applied electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light is determined by the energy band gap of the semiconductor. LEDs are typically very small. In order to improve the efficiency many researches in LEDs and its phosphor has been taking place. However still many technical challenges such as conversion losses, color control, current efficiency droop, color shift, system reliability as well as in light distribution, dimming, thermal management and driver power supply performances etc need to be met in order to achieve low cost and high efficiency. [1] Keywords: Glare, blue hazard and semiconductor. I. DIFFERENT TYPES OF LEDS MATERIALS USED: A. Gallium Arsenide (GaAs) emits infra-red light B. Gallium Arsenide Phosphide (GaAsP) emits red to infra-red, orange light C. Gallium Phosphide (GaP) emits red, yellow and green light D.
    [Show full text]