Principles of Solar Cells, LEDs and Diodes: The role of the PN junction

Principles of Solar Cells,\rLEDs and Diodes......Page 2
Contents......Page 8
Introduction......Page 12
Acknowledgements......Page 16
1 Semiconductor Physics......Page 18
1.2 The Band Theory of Solids......Page 19
1.3 The Kronig–Penney Model......Page 20
1.5 Effective Mass......Page 25
1.6 Number of States in a Band......Page 27
1.7 Band Filling......Page 29
1.8 Fermi Energy and Holes......Page 31
1.9 Carrier Concentration......Page 32
1.10 Semiconductor Materials......Page 42
1.11 Semiconductor Band Diagrams......Page 43
1.12 Direct Gap and Indirect Gap Semiconductors......Page 46
1.13 Extrinsic Semiconductors......Page 52
1.14 Carrier Transport in Semiconductors......Page 57
1.15 Equilibrium and Non-Equilibrium Dynamics......Page 60
1.16 Carrier Diffusion and the Einstein Relation......Page 62
1.17 Quasi-Fermi Energies......Page 65
1.18 The Diffusion Equation......Page 67
1.19 Traps and Carrier Lifetimes......Page 70
1.20 Alloy Semiconductors......Page 73
1.21 Summary......Page 76
Suggestions for Further Reading......Page 78
Problems......Page 80
2 The PN Junction Diode......Page 86
2.1 Introduction......Page 87
2.2 Diode Current......Page 89
2.3 Contact Potential......Page 92
2.4 The Depletion Approximation......Page 95
2.5 The Diode Equation......Page 102
2.6 Reverse Breakdown and the Zener Diode......Page 114
2.7 Tunnel Diodes......Page 117
2.8 Generation/Recombination Currents......Page 118
2.9 Ohmic Contacts, Schottky Barriers and Schottky Diodes......Page 121
2.10 Heterojunctions......Page 130
2.11 Alternating Current (AC) and Transient Behaviour......Page 132
2.12 Summary......Page 134
Suggestions for Further Reading......Page 135
Problems......Page 136
3 Photon Emission and Absorption......Page 140
3.1 Introduction to Luminescence and Absorption......Page 141
3.2 Physics of Light Emission......Page 142
3.3 Simple Harmonic Radiator......Page 145
3.4 Quantum Description......Page 146
3.5 The Exciton......Page 149
3.6 Two-Electron Atoms......Page 152
3.7 Molecular Excitons......Page 158
3.8 Band-to-Band Transitions......Page 161
3.9 Photometric Units......Page 165
3.10 Summary......Page 169
Suggestions for Further Reading......Page 170
Problems......Page 172
4 The Solar Cell......Page 176
4.1 Introduction......Page 177
4.2 Light Absorption......Page 179
4.4 Solar Cell Design and Analysis......Page 181
4.5 Thin Solar Cells......Page 189
4.6 Solar Cell Generation as a Function of Depth......Page 193
4.7 Solar Cell Efficiency......Page 196
4.8 Silicon Solar Cell Technology: Wafer Preparation......Page 201
4.9 Silicon Solar Cell Technology: Solar Cell Finishing......Page 204
4.10 Silicon Solar Cell Technology: Advanced Production Methods......Page 208
4.11 Thin Film Solar Cells: Amorphous Silicon......Page 209
4.12 Telluride/Selenide/Sulphide Thin-Film Solar Cells......Page 216
4.13 High-Efficiency Multijunction Solar Cells......Page 217
4.14 Concentrating Solar Systems......Page 220
4.15 Summary......Page 221
Suggestions for Further Reading......Page 222
Problems......Page 224
5 Light Emitting Diodes......Page 232
5.1 Introduction......Page 233
5.2 LED Operation and Device Structures......Page 234
5.3 Emission Spectrum......Page 237
5.4 Non-Radiative Recombination......Page 238
5.5 Optical Outcoupling......Page 240
5.6 GaAs LEDs......Page 242
5.7 GaAs1-xPx LEDs......Page 243
5.8 Double Heterojunction AlxGa1-xAs LEDs......Page 245
5.9 AlGaInP LEDs......Page 251
5.10 Ga1-xInxN LEDs......Page 253
5.11 LED Structures for Enhanced Outcoupling and Power Output......Page 261
5.12 Summary......Page 264
Suggestions for Further Reading......Page 265
Problems......Page 266
6 Organic Semiconductors, OLEDs and Solar Cells......Page 270
6.1 Introduction to Organic Electronics......Page 271
6.2 Conjugated Systems......Page 272
6.3 Polymer OLEDs......Page 277
6.4 Small-Molecule OLEDs......Page 283
6.6 Cathode Materials......Page 287
6.7 Hole Injection Layer......Page 288
6.9 Hole Transport Layer......Page 289
6.10 Electron Transport Layer......Page 292
6.11 Light Emitting Material Processes......Page 293
6.12 Host Materials......Page 295
6.13 Fluorescent Dopants......Page 296
6.15 Organic Solar Cells......Page 300
6.16 Organic Solar Cell Materials......Page 306
6.17 Summary......Page 309
Suggestions for Further Reading......Page 311
Problems......Page 312
Appendix 1: Physical Constants......Page 318
Appendix 2: Properties of Semiconductor Materials......Page 320
Appendix 3: The Boltzmann Distribution Function......Page 322
Index......Page 326