Nanosilicon (eBook)

Cover 1
Copyright Page 5
Contents 8
Preface 16
Chapter 1 Silicon Nanoparticles: New Photonic and Electronic Material at the Transition Between Solid and Molecule 18
1.1 Introduction 20
1.2 Synthesis 20
1.2.1 Physical Techniques 20
1.2.2 Physico-Chemical Techniques 21
1.2.3 Chemical Techniques 21
1.2.4 Electrochemical Techniques 21
1.2.5 Discretely Sized Si Nanoparticles 23
1.3 Functionalization 25
1.3.1 Initial Surface Condition 26
1.3.2 Alkylated Particles 28
1.3.3 Aggregation and Solubility 32
1.3.4 Stability in Acid 34
1.4 Spectroscopic characterization 34
1.4.1 Fourier Transform Infrared Spectroscopy 34
1.4.2 Nuclear Magnetic Resonance 36
1.4.3 Gel Permission Chromotography 37
1.4.4 X-Ray Photospectroscopy 38
1.4.5 Auger Electron Spectroscopy 38
1.4.6 Transmission Electron Microscopy 38
1.5 Optical properties 39
1.5.1 PL and Detection of Single Nanoparticles 39
1.5.2 PL Lifetime 43
1.5.3 Cathodoluminescence and Electroluminescence 44
1.5.4 Photostability Under UV and Infrared Radiation 46
1.6 Reconstitution of particles in films 46
1.6.1 Precipitation Spray 47
1.6.2 Electrodeposition: Composite Films of Metal and Nanoparticles 48
1.6.3 Silicon Sheet Roll into Tubes 49
1.6.4 Self-Assembly 50
1.7 Nonlinear optical properties 51
1.7.1 Stimulated Emission 51
1.7.2 Second Harmonic Generation 56
1.7.3 Gain and Optical Nonlinearity 56
1.8 Effect of functionalization on emission 58
1.9 Structure of particles 58
1.9.1 Luminescence Models 59
1.9.2 Computational Methods for Electronic Structure of Nanoclusters 60
1.9.3 Prototype of Hydrogenated Particles (Supermolecule) 66
1.9.4 H[sub(2)]O[sub(2)] Effect on Surface Reconstruction 68
1.9.5 Novel Si„Si Bonds (Molecular-Like Behaviour) 69
1.9.6 Structural Stability of the Prototype 71
1.9.7 Material Properties: Dielectric Constant and Effective Mass 72
1.9.8 Excited States (Molecular-Like Bands) 74
1.9.9 Collective Molecular Surface 74
1.9.10 Phonon Structure: Collective Molecular Vibration Modes 76
1.9.11 Molecular-Like Emission: Direct versus Indirect Process 77
1.9.12 X-Ray Form Factors 78
1.9.13 Effect of Termination on the Band Gap 80
1.10 Device applications 80
1.10.1 Photoelectric Conversion/UV Photodetector 81
1.10.2 Metal Oxide Silicon Memory Devices 83
1.10.3 Biophotonic Imaging 85
1.10.4 Amperometric Detection 86
1.10.5 Nanosolar Cell 88
1.10.6 Nanoink Printing 89
1.10.7 Single Electron Transistor Devices 90
1.11 Conclusion 90
Acknowledgements 91
References 91
Chapter 2 Cluster Assembled Silicon Networks 96
2.1 Introduction 97
2.2 Isolated Silicon Clusters 98
2.2.1 Small Si[sub(N)] Clusters (N & lt
2.2.3 Large Clusters (N & gt
2.3.1 Introduction 100
2.3.2 Si-Cluster-Assembled Films 100
2.3.3 Bulk Si-Cluster-Assembled Materials from Fullerenes: Clathrate Phases 114
2.4 Conclusion 127
Acknowledgements 127
References 128
Chapter 3 Metal Encapsulated Clusters of Silicon: Silicon Fullerenes and Other Polyhedral Forms 131
3.1 Introduction 132
3.2 Clusters of Elemental Silicon 135
3.3 Metal Encapsulation: A New Paradigm 138
3.3.1 Silicon Fullerenes 138
3.3.2 Metal Size Dependent Encapsulated Silicon Structures 139
3.3.3 The Electronic Factor and the Isolated Rhombus Rule 141
3.3.4 Reactivity as a Probe of Metal Encapsulation 154
3.3.5 Vibrational Properties 154
3.3.6 Empty and Endohedral Hydrogenated Fullerene Cages of Silicon 156
3.3.7 Absorption Spectra 159
3.3.8 Magnetic Clusters of Silicon 159
3.4 Summary 161
Acknowledgments 162
References 162
Chapter 4 Porous Silicon – Sensors and Future Applications 166
4.1 Introduction 167
4.2 Kinds of PS 168
4.2.1 Pore Structure in PS 168
4.2.2 PL from PS 170
4.3 PS sensors 174
4.3.1 PS Humidity Sensors 174
4.3.2 PS Chemical Sensors 178
4.3.3 PS Gas Sensors 178
4.4 Future technology 185
4.4.1 Nanoparticle Photocatalytic Coating of PS 185
4.4.2 Lithium Electrolyte-Based PS Microbattery Electrodes 187
4.5 Conclusions 189
References 189
Chapter 5 Silicon Nanowires and Nanowire Heterostructures 193
5.1 Introduction 194
5.2 Silicon nanowires 194
5.2.1 Rational Synthesis and Structural Characterization of SiNW 194
5.2.2 Electronic Properties of SiNWs 199
5.2.3 SiNWs for Nanoelectronics 207
5.2.4 Large-Scale Hierarchical Organization of SiNW Arrays 212
5.2.5 SiNWs as Nanoscale Sensors 217
5.3 SiNW heterostructures 221
5.3.1 NiSi/SiNW Heterostructures 221
5.3.2 Modulation Doped SiNWs 221
5.3.3 Branched and Hyper-Branched SiNWs 226
5.4 Summary 230
References 231
Chapter 6 Theoretical Advances in the Electronic and Atomic Structures of Silicon Nanotubes and Nanowires 234
6.1 Introduction 235
6.2 Computational approach 237
6.3 Silicon nanotubes 237
6.3.1 Metal Encapsulated Nanotubes of Silicon 239
6.3.2 Electronic Structure and Bonding Nature 242
6.3.3 Magnetism in Metal Encapsulated SiNTs 245
6.4 Germanium nanotubes 248
6.4.1 Metallic and Semiconducting Nanotubes of Ge 250
6.5 Silicon nanowires 252
6.5.1 Non-Crystalline Pristine SiNWs 254
6.5.2 Crystalline Pristine SiNWs 255
6.5.3 Band Structure of SiNWs 260
6.6 Hydrogenated nanowires 261
6.6.1 Electronic Structure of Hydrogenated SiNWs 266
6.6.2 Effects of Doping and H Defects 268
6.7 Nanowire superlattices 270
6.8 Conclusion and perspective remarks 271
Acknowledgements 272
References 272
Chapter 7 Phonons in Silicon Nanowires 275
7.1 Introduction 276
7.2 Theoretical Models for Confined Phonons 278
7.2.1 Lattice Dynamics of Si Nanowires 278
7.2.2 The Richter Model for Raman Scattering from Confined Phonons 284
7.3 Experimental Evidence of Confined Phonons in Silicon 286
7.3.1 Acoustic Phonons 286
7.3.2 Optical Phonons 290
7.3.3 Thermal Conductivity 292
7.4 Effects of Inhomogeneous Laser Heating on Raman Lineshape 295
7.4.1 Stokes–AntiStokes Ratio as a Probe of Laser Heating of Si Nanowires 296
7.4.2 Evolution of the Raman Band Asymmetry with Laser Flux 297
7.4.3 Modification of Richter’s Lineshape Function to Include Inhomogeneous Heating 299
7.5 Summary and Conclusions 302
Acknowledgements 302
References 303
Chapter 8 Quasi-One-Dimensional Silicon Nanostructures 306
8.1 Introduction 307
8.2 Silicon nanowires 307
8.2.1 Pentagonal Silicon Wires 307
8.2.2 Hydrogen-Passivated Silicon Wires 314
8.3 Metal silicide 317
8.3.1 Endohedral Silicon Nanotubes 318
8.3.2 Yttrium Silicide NW 324
8.3.3 Energy Decomposition 325
References 329
Acknowledgements 328
Chapter 9 Low-dimensional Silicon as a Photonic Material 331
9.1 The need of a Silicon-Based Photonics 331
9.2 Various Approaches to a Silicon Light Source 333
9.2.1 Silicon Raman Laser 334
9.2.2 Bulk Silicon Light Emitting Diodes 336
9.3 Optical Gain in Silicon Nanocrystals 338
9.3.1 CW and TR Measurements 339
9.3.2 Gain Model: Four-Level System 342
9.3.3 Other Key Ingredients 344
9.4 Er Coupled Si Nanocrystal Optical Amplifiers 345
9.4.1 E[sup(3+)] Internal Transition 346
9.4.2 E[sup(3+)] and Si-nc Interactions 347
9.4.3 E[sup(3)] Cross Sections 347
9.5 Conclusions 349
Acknowledgements 350
References 350
Chapter 10 Nanosilicon Single-Electron Transistors and Memory 352
10.1 Introduction 352
10.1.1 Single-Electron and Quantum Confinement Effects 354
10.2 Nanosilicon SETs 358
10.2.1 Conduction in Continuous Nanocrystalline Silicon Films 358
10.2.2 Silicon Nanowire SETs 360
10.2.3 Point-Contact SETs: Room Temperature Operation 363
10.2.4 Grain-BoundaryŽ Engineering 367
10.2.5 Single-Electron Transistors Using Silicon Nanocrystals 368
10.2.6 Comparison with Crystalline Silicon SETs 369
10.3 Electron Coupling Effects in Nanosilicon 369
10.3.1 Electrostatic Coupling Effects 371
10.3.2 Electron Wavefunction Coupling Effects 371
10.4 Nanosilicon memory 373
References 375
Index 378
A 378
B 378
C 378
D 378
E 378
F 379
G 379
H 379
I 379
K 379
L 379
M 380
N 380
O 380
P 380
Q 381
R 381
S 381
T 384
U 384
V 384
W 384
X 385
Y 385
Z 385