Zinc Oxide Materials for Electronic and Optoelectronic Device Applications
索书号 57/L781
Zinc Oxide (ZnO) powder has been widely used as a white paint pigment and industrial processing chemical for nearly 150 years. However, following a rediscovery of ZnO and its potential applications in the 1950s, science and industry alike began to realize that ZnO had many interesting novel properties that were worthy of further investigation.
ZnO is a leading candidate for the next generation of electronics, and its biocompatibility makes it viable for medical devices. This book covers recent advances including crystal growth, processing and doping and also discusses the problems and issues that seem to be impeding the commercialization of devices.
Table of Contents
Series Preface xv
Preface xvii
List of Contributors xxi
1 Fundamental Properties of ZnO 1
T. C. Collins and R. J. Hauenstein
1.1 Introduction 1
1.1.1 Overview 1
1.1.2 Organization of Chapter 2
1.2 Band Structure 2
1.2.1 Valence and Conduction Bands 2
1.3 Optical Properties 5
1.3.1 Free and Bound Excitons 5
1.3.2 Effects of External Magnetic Field on ZnO Excitons 6
1.3.3 Strain Field 8
1.3.4 Spatial Resonance Dispersion 9
1.4 Electrical Properties 10
1.4.1 Intrinsic Electronic Transport Properties 10
1.4.2 n-type Doping and Donor Levels 11
1.4.3 p-type Doping and Dopability 13
1.4.4 Schottky Barriers and Ohmic Contacts 17
1.5 Band Gap Engineering 19
1.5.1 Homovalent Heterostructures 20
1.5.2 Heterovalent Heterostructures 22
1.6 Spintronics 22
1.7 Summary 25
References 25
2 Optical Properties of ZnO 29
D. C. Reynolds, C. W. Litton and T. C. Collins
2.1 Introduction 29
2.2 Free Excitons 29
2.3 Strain Splitting of the G5 and G6 Free Excitons in ZnO 35
2.4 Photoluminescence from the Two Polar Faces of ZnO 36
2.5 Bound-Exciton Complexes in ZnO 38
2.6 Similarities in the Photoluminescence Mechanisms of ZnO and GaN 46
2.7 The Combined Effects of Screening and Band Gap Renormalization on the Energy of Optical Transitions in ZnO and GaN 51
2.8 Closely Spaced Donor–Acceptor Pairs in ZnO 55
2.9 Summary 58
References 58
3 Electrical Transport Properties in Zinc Oxide 61
B. Claflin and D. C. Look
3.1 Introduction 61
3.2 Hall-Effect Analysis 62
3.2.1 Single-Band Conduction 62
3.2.2 Two-Band Mixed Conduction 65
3.2.3 Conducting Surface Layers 66
3.3 Donor States and n-type Doping 66
3.3.1 Native Point Defects – Donors 68
3.3.2 Substitutional Donors 69
3.4 Hydrogen 69
3.5 Acceptor States and p-type Doping 70
3.5.1 Native Point Defects – Acceptors 71
3.5.2 Substitutional Acceptors 72
3.6 Photoconductivity 76
3.7 Summary 78
References 78
4 ZnO Surface Properties and Schottky Contacts 87
Leonard J. Brillson
4.1 Historical Background of Schottky Contacts on ZnO 87
4.1.1 ZnO Surface Effects 88
4.1.2 Early Schottky Barrier Studies 90
4.2 Recent Schottky Barrier Studies 91
4.2.1 Surface Cleaning in Vacuum 91
4.2.2 Surface Cleaning Effects on Impurities and Defects 92
4.3 The Influence of Surface Preparation on Schottky Barriers 93
4.4 The Influence of Defects on Schottky Barriers 97
4.5 The Influence of ZnO Polarity on Schottky Barriers 102
4.6 The Influence of Chemistry 103
4.7 Charge Transport and Extended Metal–ZnO Schottky Barriers 108
4.8 Conclusion 110
Acknowledgements 110
References 110
5 Native Point Defects and Doping in ZnO 113
Anderson Janotti and Chris G. Van de Walle
5.1 Introduction 113
5.2 Theoretical Framework 114
5.3 Native Point Defects 115
5.3.1 Oxygen Vacancies 117
5.3.2 Zinc Interstitials 119
5.3.3 Zinc Antisites 120
5.3.4 Zinc Vacancies 121
5.3.5 Defect Migration 121
5.4 Donor Impurities 125
5.4.1 Aluminum, Gallium and Indium 125
5.4.2 Fluorine 125
5.4.3 Hydrogen 125
5.5 Acceptor Impurities 129
5.5.1 Lithium 129
5.5.2 Copper 129
5.5.3 Nitrogen 129
5.5.4 Phosphorous, Arsenic and Antimony 130
5.5.5 Co-Doping 130
5.6 Isoelectronic Impurities 131
Acknowledgements 131
References 131
6 Spectral Identification of Impurities and Native Defects in ZnO 135
B.K. Meyer, D.M. Hofmann, J. Stehr and A. Hoffmann
6.1 Introduction 135
6.2 Optical Spectroscopy 136
6.2.1 Excitons Bound to Shallow Donors 136
6.2.2 Recombinations Caused by Nitrogen and Arsenic Doping 145
6.3 Magnetic Resonance Investigations 153
6.3.1 Shallow Donors 154
6.3.2 Deep Level Defects 158
6.3.3 Extrinsic Acceptors: Li, Na and N 161
6.3.4 Intrinsic Acceptors 166
References 166
7 Vapor Transport Growth of ZnO Substrates and Homoepitaxy of ZnO Device Layers 171
Gene Cantwell, Jizhi Zhang and J.J. Song
7.1 Introduction 171
7.2 Transport Theory and Comparison with Growth Data 172
7.3 Characterization 175
7.3.1 Crystallinity 175
7.3.2 Purity 176
7.3.3 Electrical 177
7.3.4 Optical 178
7.4 In-situ Doping 180
7.5 ZnO Homoepitaxy 181
7.5.1 Substrate Preparation 182
7.5.2 Homoepitaxial Films on c-plane SCVT ZnO Substrates 183
7.5.3 ZnO Homoepitaxial Films on a-plane SCVT ZnO Substrates 185
7.6 Summary 185
Acknowledgement 186
References 186
8 Growth Mechanisms and Properties of Hydrothermal ZnO 189
M. J. Callahan, Dirk Ehrentraut, M. N. Alexander and Buguo Wang
8.1 Introduction 189
8.2 Overview of Hydrothermal Solution Growth 190
8.3 Thermodynamics of Hydrothermal Growth of ZnO 190
8.3.1 Solubility of ZnO in Various Aqueous Media 190
8.3.2 ZnO Phase Stability in H2O System 191
8.4 Hydrothermal Growth Techniques 194
8.4.1 Hydrothermal Growth of ZnO Powder 194
8.4.2 Hydrothermal Crystal Growth of ZnO Single Crystals 194
8.4.3 Industrial Growth of Large ZnO Crystals 197
8.5 Growth Kinetics of Hydrothermal ZnO 200
8.5.1 Crystallographic Structure of Hydrothermal ZnO 200
8.5.2 Growth Rates of the Crystallographic Facets of Hydrothermal ZnO 200
8.6 Properties of Bulk Hydrothermal ZnO 205
8.6.1 Extended Imperfections (Dislocations, Voids, etc.) and Surface Studies 205
8.6.2 Impurities 208
8.6.3 Electrical Properties 210
8.6.4 Optical Properties 213
8.6.5 Etching and Polishing 215
8.7 Conclusion 217
Acknowledgements 217
References 218
9 Growth and Characterization of GaN/ZnO Heteroepitaxy and ZnO-Based Hybrid Devices 221
Ryoko Shimada and Hadis Morkoç
9.1 Introduction 221
9.2 Growth of GaN/ZnO 222
9.3 Compositional Analysis 230
9.4 Structural Analysis 232
9.5 Surface Studies 235
9.6 Optical Properties 237
9.6.1 Transmission Analysis 237
9.6.2 Cathodoluminescence Analysis 239
9.6.3 Photoluminescence Analysis 242
9.7 Electrical Properties 249
9.8 GaN/ZnO Hybrid Devices 252
9.8.1 Hybrid ZnO/GaN Heterojunction LED 253
9.8.2 ZnO-based Hybrid Microcavity 259
9.9 Conclusions 261
Acknowledgements 262
References 262
10 Room Temperature Stimulated Emission and ZnO-Based Lasers 265
D.M. Bagnall
10.1 Introduction 265
10.2 Emission Mechanisms 266
10.3 Stimulated Emission 267
10.3.1 Bulk ZnO 267
10.3.2 Epitaxial Layers 267
10.3.3 Quantum wells and Superlattices 270
10.3.4 ZnMgO/ZnO Structures 270
10.3.5 ZnO/ZnCdO Structures 272
10.4 Zinc Oxide Lasers 274
10.4.1 Introduction 274
10.4.2 Microstructural Lasers 275
10.4.3 Powder Lasers 278
10.4.4 Nanowire Lasers 279
10.4.5 ZnO Laser Diodes 280
10.5 Conclusions 281
References 282
11 ZnO-Based Ultraviolet Detectors 285
Jian Zhong and Yicheng Lu
11.1 Introduction 285
11.2 Photoconductivity in ZnO 288
11.2.1 Persistent Photoconductivity 293
11.2.2 Negative Photoconductivity 295
11.3 ZnO Film-Based UV Photodetectors 297
11.3.1 Photoconductive UV Detector 297
11.3.2 Schottky Barrier UV Photodetectors 301
11.3.3 Integrated Surface Acoustic Wave and Photoconductive Wireless UV Detectors 305
11.3.4 Photodetectors Using ZnO TFT 314
11.3.5 MgxZn1_xO UV Photodetector 315
11.4 ZnO NW UV Photodetectors 318
11.4.1 Photoconductive Gain in a ZnO NW 318
11.4.2 Noise Characteristics of ZnO NW UV Photodetector 323
11.5 Conclusions 325
Acknowledgements 325
References 326
12 Room-Temperature Stimulated Emission from ZnO Multiple Quantum Wells Grown on Lattice-Matched Substrates 331
Takayuki Makino, Yusaburo Segawa, Masashi Kawasaki and Hideomi Koinuma
12.1 Introduction 331
12.2 Experimental Details 333
12.3 Quantum Confinement Effect of Excitons in QWs 333
12.4 Exciton–Phonon Interaction in QWs 336
12.5 The Localization Mechanism of the Exciton in a QW 337
12.6 Time-Resolved Luminescence in ZnO QWs 341
12.7 Stimulated Emission in MQWs 342
12.8 Summary 346
Acknowledgements 347
References 347
Index 351
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