Inorganic Nanowires: Applications, Properties, and Characterization

456 Pages·2009·11.906 MB·English

by  M. Meyyappan, Mahendra K. Sunkara

INORGANIC NANOWIRES
Nanomaterials and Their Applications
Series Editor: M. Meyyappan
Inorganic Nanowires: Applications, Properties, and Characterization
M. Meyyappan, Mahendra Sunkara
Inorganic Nanoparticles: Synthesis, Applications, and Perspectives
Claudia Altavilla, Enrico Ciliberto, Editors
INORGANIC NANOWIRES
Applications, Properties, and
Characterization
M. Meyyappan
NASA Research Center, Moffett Field
California, USA
Mahendra Sunkara
University of Louisville
Kentucky, USA
Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
Cover Image: Vertical surround-gate transistor (Courtesy of H.T. Ng) and vertical zinc oxide nanowires
(Courtesy of H.T. Ng and Pho Nguyen). The image at the bottom depicts a laser mode profile along a nanowire
laser, showing waves being emitted from the top end and into the substrate (Courtesy of Cun-Zheng Ning).
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Version Date: 20131120
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Contents
Preface ......................................................................................................................xi
Authors ...................................................................................................................xv
1. Introduction .....................................................................................................1
References .........................................................................................................5
2. Historical Perspective ....................................................................................7
References .......................................................................................................15
3. Growth Techniques ......................................................................................17
3.1 Introduction ...........................................................................................17
3.2 Liquid-Phase Techniques .....................................................................17
3.2.1 Template-Based Methods .........................................................18
3.2.1.1 Template Preparation ..................................................18
3.2.1.2 Deposition Methods ...................................................23
3.2.2 Template-Free Methods ............................................................32
3.2.2.1 Hydrothermal Method ...............................................32
3.2.2.2 Sonochemical Method ...............................................34
3.2.2.3 Surfactant-Assisted Growth:
Soft Directing Agents.................................................35
3.2.2.4 Catalyst-Assisted Solution-Based Approaches .......36
3.3 Vapor-Phase Techniques ......................................................................37
3.3.1 One-Dimensional Growth Concepts ......................................38
3.3.1.1 Vapor–Liquid–Solid Schemes Using
Foreign Metal Clusters ...............................................38
3.3.1.2 Vapor–Liquid–Solid Schemes Using
Low-Melting Metal Clusters .....................................39
3.3.1.3 Vapor–Liquid–Solid Schemes Using Large
Size, Molten Metal Clusters.......................................40
3.3.1.4 Vapor–Solid–Solid Scheme ........................................40
3.3.1.5 Oxygen-Assisted Growth (OAG) Scheme ................40
3.3.2 Source Generation and Reactors for Vapor-Phase
Synthesis of Nanowires ............................................................40
3.3.2.1 Thermal Evaporation ..................................................41
3.3.2.2 Laser Ablation .............................................................42
3.3.2.3 Metal Organic Chemical Vapor Deposition ............44
3.3.2.4 Chemical and Molecular Beam Epitaxy ..................47
3.3.2.5 Plasma Arc Discharge–Based Techniques ..............49
3.4 Bulk Production Methods ....................................................................50
v
vi Contents
3.4.1 Hot Filament CVD Method ......................................................50
3.4.2 Supercritical Fluid Approach ..................................................52
3.4.3 Direct Oxidation Schemes Using Plasma ..............................52
3.4.4 Direct Gas-Phase Reactions Using Plasma Discharges .......53
3.5 Future Developments ...........................................................................55
References .......................................................................................................57
4. Thermodynamic and Kinetic Aspects of Nanowire Growth ..............61
4.1 Introduction ...........................................................................................61
4.2 Thermodynamic Considerations for Vapor–Liquid–Solid
Growth ....................................................................................................63
4.2.1 Thermodynamic Considerations of Nucleation from
Molten Metal Droplets ..............................................................63
4.2.1.1 Gibbs–Thompson Relationship .................................63
4.2.1.2 Nucleation from Molten Metal Alloy Droplet ........65
4.2.1.3 Nucleation from Various Molten
Metal Droplets .............................................................66
4.2.1.4 Thermodynamic Estimation of
Supersaturation for Spontaneity of Nucleation ......70
4.2.1.5 Rational Choice of Metal for Tip-Led Growth
of Nanowires (Avoiding Nucleation) ........................73
4.2.1.6 Experimental Conditions for Promoting
Tip-Led Growth Using Any Molten Metal ..............76
4.2.2 Interfacial Energy and Tip-Led Growth ................................77
4.2.2.1 Role of Interfacial Energy in the Nanowire
Growth Stability .........................................................77
4.2.2.2 Role of Interfacial Energy in Nanowire
Faceting ........................................................................81
4.2.2.3 Role of Interfacial Energy on the Nanowire
Growth Direction ........................................................85
4.3 Kinetic Considerations of Nanowire Growth
under VLS Growth ...............................................................................87
4.3.1 Kinetics of Vapor–Liquid–Solid Equilibrium ........................87
4.3.2 Role of Direct Impingement in Growth Kinetics ..................89
4.3.3 Role of Surface Diffusion in Growth Kinetics ......................91
4.3.4 Direct Impingement and Diffusion ........................................94
4.3.5 Role of Surface Diffusion on the Metal Droplet ...................95
4.3.6 Role of Interwire Spacing .........................................................97
References .......................................................................................................98
5. Modeling of Nanowire Growth ...............................................................101
5.1 Introduction .........................................................................................101
5.2 Energetics of Stable Surface Faceting: Silicon
Nanowire Example .............................................................................102
5.3 Simulation of Individual Nanowire Growth ..................................104
Contents vii
5.3.1 Simulation Methodology ........................................................105
5.3.2 Kinetic Monte Carlo Simulation Results ..............................108
5.3.3 Experimental Results on Growth Direction
and Surface Faceting ..............................................................112
5.4 Modeling of Multiple Nucleation and Growth of
One-Dimensional Structures .............................................................115
5.5 Modeling Nanowire Array Growth .................................................117
References .....................................................................................................121
6. Semiconducting Nanowires .....................................................................123
6.1 Introduction .........................................................................................123
6.2 Silicon Nanowires ...............................................................................123
6.2.1 SiCl/H System .......................................................................124
4 2
6.2.2 Silane Feedstock in VLS Growth ..........................................134
6.2.3 Other Sources ..........................................................................135
6.2.4 Oxide-Assisted Growth ..........................................................136
6.2.5 Template-Assisted Synthesis .................................................137
6.2.6 Plasma Enhancement .............................................................138
6.2.7 Doping of SiNWs .....................................................................139
6.2.8 Properties of SiNWs ................................................................140
6.3 Germanium Nanowires .....................................................................142
6.3.1 Synthesis Using Germanium Powder ..................................143
6.3.2 Germane and Related Sources ..............................................146
6.4 Catalyst Choice ....................................................................................147
6.5 III–V Nanowires ..................................................................................148
6.5.1 GaAs Nanowires .....................................................................149
6.5.2 InAs Nanowires ......................................................................152
6.5.3 InP Nanowires .........................................................................152
6.5.4 GaP Nanowires ........................................................................154
References .....................................................................................................155
7. Phase Change Materials ............................................................................161
7.1 Introduction ..........................................................................................161
7.2 Phase Change Nanowire Growth .....................................................162
7.3 Properties Relevant to PRAM ............................................................167
References .....................................................................................................169
8. Metallic Nanowires ....................................................................................171
8.1 Bismuth Nanowires ............................................................................171
8.2 Silver Nanowires .................................................................................173
8.3 Copper Nanowires ..............................................................................174
8.4 Nickel Nanowires ...............................................................................176
8.5 Zinc Nanowires ...................................................................................178
References .....................................................................................................180
viii Contents
9. Oxide Nanowires ........................................................................................183
9.1 Introduction .......................................................................................183
9.2 Synthesis Methodologies .................................................................184
9.2.1 Catalyst-Assisted Synthesis ................................................184
9.2.2 Direct Oxidation Schemes Using
Low-Melting Metals ............................................................190
9.2.2.1 Direct Oxidation of Molten Metal Clusters .......190
9.2.2.2 Direct Chemical/Reactive Vapor Deposition
of Low-Melting Metal Oxides .............................193
9.2.3 Chemical Vapor Transport or Deposition of
High-Melting Metal Oxides ...............................................196
9.2.4 Plasma and Thermal Oxidation of Foils ...........................202
9.3 Directed Growth and Morphological Control ..............................206
9.3.1 Branched Nanowire Structures .........................................206
9.3.2 Networking of Nanowires .................................................208
9.3.3 Nanobelts ..............................................................................209
9.3.4 Tubular Nanostructures .....................................................212
9.3.4.1 High-Melting Metal Oxides .................................212
9.3.4.2 Low-Melting Metal Oxides ..................................213
9.4 Oxygen Vacancies, Doping, and Phase Transformation .............214
9.4.1 Oxygen Vacancies ................................................................214
9.4.2 Doping and Alloying ..........................................................216
9.4.3 Phase Transformation of Metal Oxide Nanowires .........217
References .....................................................................................................220
10. Nitride Nanowires ......................................................................................225
10.1 Introduction .......................................................................................225
10.2 Synthesis of Group III–Nitride Nanowires ...................................225
10.2.1 Catalyst-Assisted Synthesis ................................................226
10.2.1.1 Choice of Precursors ............................................229
10.2.1.2 Substrates for Epitaxial Array Growth .............230
10.2.1.3 Choice of Catalysts and Process Variables .......231
10.2.1.4 Control of Nanowire Growth Direction ...........232
10.2.2 Direct Reaction and Self-Catalysis Schemes ...................233
10.2.2.1 Control of Growth Direction ..............................239
10.2.3 Synthesis of Nanotubes ......................................................240
10.2.4 Micro/Nanomorphologies .................................................243
10.2.4.1 III-Nitride Nanobelts ...........................................243
10.2.4.2 Tapered Morphologies ........................................245
10.3 Branching of Nanowires ..................................................................247
10.3.1 Homobranching or “Tree-Like” Structures .....................247
10.3.2 Heterobranching ..................................................................248
10.4 Diameter Reduction of III-Nitride Nanowires ..............................249
10.5 Direction-Dependent Properties .....................................................252
References .....................................................................................................254
Contents ix
11. Other Nanowires ........................................................................................257
11.1 Antimonides .......................................................................................257
11.2 Selenides .............................................................................................260
11.2.1 Zinc Selenide .........................................................................260
11.2.2 Other Selenides ....................................................................263
11.3 Tellurides ............................................................................................264
11.3.1 Bismuth Telluride .................................................................264
11.3.2 Cadmium Telluride..............................................................265
11.3.3 Other Tellurides ...................................................................265
11.4 Sulfi des ................................................................................................266
11.4.1 Zinc Sulfi de ...........................................................................266
11.4.2 Other Sulfi des .......................................................................267
11.5 Silicides ...............................................................................................269
References .....................................................................................................269
12. Applications in Electronics .......................................................................275
12.1 Introduction .......................................................................................275
12.2 Silicon Nanowire Transistors ..........................................................278
12.3 Vertical Transistors ...........................................................................280
12.4 Germanium Nanowire Transistors ................................................284
12.5 Zinc Oxide and Other Nanowires in Electronics .........................286
12.6 III–V Transistors ................................................................................289
12.7 Memory Devices ...............................................................................290
12.7.1 Phase-Change Random Access Memory ..........................292
References .....................................................................................................296
13. Applications in Optoelectronics ..............................................................299
13.1 Introduction .......................................................................................299
13.2 Photodetectors ...................................................................................299
13.3 Light-Emitting Diodes ......................................................................303
13.4 Nanoscale Lasers ...............................................................................306
References .....................................................................................................310
14. Applications in Sensors ............................................................................313
14.1 Introduction .......................................................................................313
14.2 Chemical Sensors ..............................................................................314
14.2.1 Sensor Requirements and the Role
of Nanomaterials ..................................................................314
14.2.2 Nanowires in Sensor Fabrication ......................................317
14.2.3 Sensing Mechanisms ...........................................................327
14.2.4 Selectivity and Electronic Nose .........................................331
14.3 Biosensors ...........................................................................................337
14.3.1 Nanoelectrode Arrays .........................................................340
References .....................................................................................................344