Semiconductor Superlattices and Interfaces (eBook)

Front Cover 1
Semiconductor Superlattices and Interfaces 3
Copyright Page 4
Table of Contents 5
Preface 13
Chapter 1. The evolution of semiconductor quantum structures. Do-it-yourself quantum mechamics 19
1. Introduction 19
2. Epitaxy and superlattice growth 23
3. Resonant tunneling in an electric field 24
4. Transport and optical properties in superlattices and quantum wells subject to an applied electric field 27
5. Conclusion 38
Chapter 2. Physics and engineering of heterojunction band lineups 43
1. Introduction: from bandgap science to bandgap engineering 43
2. Internal photoemission: a new weapon in today's experimental arsenal for studying heterojunction band lineups 45
3. Heterojunction band lineup control: empirical considerations 49
4. Practical cases of band lineup control 50
5. Future avenues 53
Chapter 3. Theoretical models on the formation of semiconductor interface barriers 57
1. Introduction 57
2. Metal-semiconductor interfaces 58
3. Semiconductor-semiconductor interfaces 69
4. Conclusions 73
Chapter 4. Semiconductor interfaces 77
1. Introduction 77
2. Isovalent substitutions 80
3. Heterovalent substitutions 85
4. Band offsets and linear-response scheme 87
5. Heterovalent intralayers: interface dipoles 94
6. Conclusions 101
Chapter 5. The strain release in mismatched semiconductor heterostructures 105
1. Introduction 105
2. Formalism and results of the elasticity theory 106
3. Critical-thickness theories 109
4. Experimental techniques 114
5. Experimental results and discussion 116
Chapter 6. Optical investigation of interfaces 123
1. Introduction 123
2. Si-electrolyte and Si-Si02 interface 123
3. Thick epitaxial Si layers 129
4. Highly doped Si layers 133
Chapter 7. Optical properties of silicides 141
1. Introduction 141
2. Chemical bond and electronic states in silicides 143
3. Optical properties of transition metal silicides pag 149
Chapter 8. Quantum size effect in low-dimensional semiconductors 175
1. Theoretical aspects 175
2. Fabrication of quantum wires and quantum dots 177
3. Main experiments 179
Chapter 9. Relaxation dynamics in GaAs/ZAlx.Ga1_x.As quantum well heterostructures 187
1. Introduction 187
2. Experimental 189
3. Samples 190
4. Carrier recombination in GaAs/Al0.3 Ga0.7As quantum wells 190
5. Tunnelling in ADQW structures 198
6. Summary 202
Chapter 10. Excitons and polaritons in quantum wells 205
1. Introduction 205
2. Excitons in semiconductors 207
3. Exciton-polariton states 209
4. Excitons in quantum wells 213
5. Quantum well polaritons 219
6. Extension to quantum wires and quantum dots 230
Chapter 11. Envelope function approach to electronic states in heterostructures 235
1. Introduction 235
2. Envelope function description of electronic states 236
3. Examples of results for some systems 245
4. External magnetic fields 251
5. Excitons in quantum wells 255
Chapter 12. Ab initio calculation of phonon spectra in semiconductors: from pure crystals to alloys and superlattices 261
1. Introduction 261
2. Theoretical framework and computational techniques 266
3. Some results for pure crystals 272
4. Phonons in semiconductor alloys 275
5. Vibrational properties of GaAs/AlAs superlattices 285
6. Summary and outlook 292
Chapter 13. Compositional disorder in AlGaAs superlattices: bond charge model calculations of vibrational features and optical spectra 297
1. Introduction 297
2. Outline of the computational model and related techniques 299
3. Vibrational properties of GaAs and AlAs mixtures 309
4. Order-disorder interplay 319
Chapter 14. Interaction of light with «folded» acoustic waves in semiconductor superlattices 331
1. Introduction 331
2. Salient features of superlattice phonon modes 331
3. Experimental determination of the FLA dispersion curves 333
4. Intensity of the FLA peaks 337
5. Effects of the acoustic attenuation and optical absorption 338
6. Disorder and intermixing effects on the «acoustic» phonons 343
7. Conclusion 348
Chapter 15. Photoreflectance study of GaAs/AlxGa1-xAs single quantum well and strained InxGa1As/GxAs superlattices 351
1. Introduction 351
2. Experiment 352
3. Line shape analysis 353
4. Single quantum wells in GaAs/AlxGa1-xAs 355
5. Strained InxGa1-xAs/GaAs superlattices 362
Chapter 16. Wannier-Stark quantization in semiconductor superlattices: physics and applications 369
1. Introduction 369
2. Theoretical aspects 370
3. Experimental results 374
4. Electro-optical applications 379
5. Conclusion 381
Chapter 17. Thermal and thermo-electric transport properties of quantum point contacts 383
1. Introduction 383
2. Theoretical background 384
3. Experiments 388
4. Conclusions 394
Appendix 394
Chapter 18. Band structure engineering and its device applications 397
1. Introduction 397
2. Abrupt heterointerfaces as launching ramps: ballistic devices 398
3. Bandgap grading 401
4. Abrupt heterointerfaces as electronic mirrors: quantum devices 404
5. Ultimate bandgap engineering: tunable discontinuities 410
6. Nonlinear optical properties of coupled-quantum-well molecules 411
Chapter 19. The physics of nanofabrication 417
1. Introduction 417
2. Pattern definition and pattern transfer 417
3. Resolution of the pattern definition step 417
4. Photolithography 418
5. Electron beam lithography 419
6. Ion beam lithography 421
7. Pattern transfer—additive processing 421
8. Etching 422
9. Dry-etching damage 424
10. Conclusions 426
Chapter 20. Molecular-beam epitaxy of advanced structures based on III-V compounds 429
1. Introduction 429
2. Fundamentals of the MBE growth process 430
3. Technology of MBE 434
4. MBE growth fronts and interfaces 437
5. Epitaxial structures 439
6. Conclusions 446
Chapter 21. Problems in optical properties of semiconductors and their solutions 453
1. Introduction 453
2. Plasmons, carrier effective masses 454
3. Symmetry effects 459
4. Phonons in bulk crystals and superlattices 465
5. Coupling mechanisms in Raman scattering by phonons 468
6. Surface excitations 474
7. Stress and strain effects 479
8. Impurities, isotopic disorder 481
9. Widths and self-energies of excitons 486