Rare Earth Doped III-Nitrides for Optoelectronic and Spintronic Applications

by O'Donnell, Kevin; Dierolf, Volkmar

• ISBN13: 9789048128761
• ISBN10: 9048128765
• Format: Hardcover
• Copyright: 2010-08-30
• Publisher: Springer Verlag

Summary

This book summarises recent progress in the science and technology of rare-earth doped nitrides, providing a snapshot of the field at a critical point in its development.Improved theoretical understanding of the behaviour of f-electrons in solids, driven by accelerating computational capability, has coincided with an improved ability of crystal growers to incorporate rare earth elements reproducibly in wide bandgap semiconductor hosts that are favoured for optoelectronic and spintronic applications. The device possibilities of these advanced materials are promising but by no means well-developed. Following a review of the theoretical background, this book explores the preparation of materials, either through in-situ growth or ion implantation/annealing, the characterisation of these materials and their incorporation in existing and prospective devices. Featuring contributions from leading researchers in Europe, the USA and Japan, the book will be a valuable resource for academics, advanced students and industrial scientists.

Table of Contents

Theoretical Modelling of Rare Earth Dopants in GaN	p. 1
Introduction	p. 1
Theoretical Modelling	p. 2
Quantum Mechanical Methods	p. 3
4f Electrons	p. 5
The RE Pseudopotential	p. 6
Basis Functions	p. 7
Semi-Empirical Modelling	p. 7
Semi-Empirical LDA+U	p. 8
Clusters and Supercells	p. 10
Kohn-Sham and Occupancy Levels	p. 11
Formation Energies, Vibrational Modes, Energy Level	p. 11
Er, Eu and Tm in GaN	p. 13
Treatment of f-Electrons - Substitutional ErGa	p. 15
Deep Level Transient Spectroscopy	p. 16
Excitation and Emission m GaN:Eu	p. 17
RE Defects in A1N	p. 18
Conclusions	p. 20
References	p. 21
RE Implantation and Annealing of III-Nitrides	p. 25
Introduction	p. 26
Implantation Damage in GaN	p. 27
Implantation Geometry Dependence	p. 27
Fluence Dependence	p. 29
Implanatation Temperature Dependence	p. 35
Annealing and Optical Activation of RE Ions	p. 37
Optical Activation by High Temperature Annealing	p. 38
Influence of Annealing Atmosphere	p. 39
Annealing of A1N-Capped Samples	p. 42
Annealing at Ultrahigh Pressure	p. 46
RE Doping of A1N and A1N-Containing Ternary Alloys	p. 48
Summary	p. 52
References	p. 52
Lattice Location of RE Impurities in III-Nitrides	p. 55
Introduction	p. 56
Lattice Sites in Wurtzite Crystals	p. 57
Experimental Lattice Site Determination	p. 59
Ion Beam Channelling	p. 60
Emission Channelling	p. 61
X-Ray Absorption Fine Structure (XAFS)	p. 65
Hypertinc Interactions	p. 66
Lattice Site in Wurtzite Crystals	p. 66
Lattice Location of High-Fluence GaN:RE Implants by RBS/C	p. 66
Lattice Location of Low-Fluence GaN:RE by EC	p. 71
RE Lattice Site Dependence on Experimental Parameters	p. 79
Dependence on the Fluence	p. 79
Dependence on the Implantation Geometry	p. 83
Dependence on the Implantation Temperature	p. 86
Co-Implantation of RE and O or Other Impurity	p. 86
The Effect of Sample Mosaicity on Determining the Lattice Sites: A1N vs. GaN	p. 90
Conclusions	p. 94
Acknowledgements	p. 95
References	p. 96
Electroluminescent Devices Using RE-Doped III-Nitrides	p. 99
Introduction	p. 99
General Treatment of EL devices	p. 101
III-N:RE EL Devices	p. 102
Light Emitting Diode with RE-doped GaN Active Layer	p. 109
Summary	p. 111
References	p. 112
Er-Doped GaN and InxGa1-xN for Optical Communications	p. 115
Introduction	p. 116
Er Doping of GaN and InGaN by Ion Implantation	p. 117
In Situ Er Doping of GaN by MBE and HVPE	p. 129
MOCVD Growth of Er-Doped III-Nitrides	p. 136
Er-Doped GaN	p. 138
Er-Doped InGaN	p. 142
Current-Injected 1.54 ¿m LEDs Based on GaN:Er	p. 150
Er-Doped Nitride Amplifier (EDNA) Development	p. 152
Summary	p. 155
Acknowledgements	p. 155
References	p. 156
Rare-Earth-Doped GaN Quantum Dots	p. 159
Introduction	p. 159
Growth of GaN QDs	p. 161
Undoped Dots	p. 161
Rare-Earth-Doped Dots	p. 163
Optical Properties	p. 168
Eu-Doped GaN QDs Embedded in A1N	p. 168
Eu-Doped InGaN QDs Embedded in GaN	p. 171
Tm-Doped Dots	p. 172
Tb-Doped GaN QDs	p. 175
Photoluminescence Dynamics of RE-Doped GaN QDs	p. 177
Electroluminescence of Rare Earth-Doped GaN QDs	p. 183
Conclusion	p. 185
Acknowlegements	p. 186
References	p. 186
Visible Luminescent RE-doped GaN, AlGaN and AlInN	p. 189
Introduction to Luminescence of RR-Doped GaN	p. 189
Preparation of Samples	p. 192
Cathodoluminescence and X-Ray Microanalysis	p. 192
Annealing Temperature Dependence of RE Luminescence	p. 197
Site Multiplicity in GaN:Eu Revealed by Photoluminescence Spectroscopy	p. 200
Luminescence of Eu Ions in AlGaN across the Entire Alloy Composition Range	p. 205
Luminescence of RE Ions in AlInN Hosts	p. 213
Conclusion	p. 216
Acknowledgements	p. 217
References	p. 217
Combined Excitation Emission Spectroscopy (CEES) of RE Ions in Gallium Nitride	p. 221
Introduction	p. 221
RE Ions in GaN: General Considerations	p. 222
CEES Experimental Setup	p. 223
Application of CEES to Erbium in GaN	p. 226
Introduction	p. 226
Direct Excitation of 1.5 ¿m Emission	p. 226
Two-Step Excitation of 980 nm and 820 nm Emission	p. 231
Three-Step Excitation of 670 nm and 550 nm Emission	p. 236
Direct Excitation of 670 nm and 550 nm Emission	p. 237
Comparison of in situ Doped MBE and MOCVD Grown GaN:Er Samples	p. 239
Above Bandgap Excitation of 1.5 ¿m Emission	p. 241
Summary of CEES Spectroscopy of GaN:Er	p. 242
Application of CEES to Neodymium in GaN	p. 242
Introduction and Experimental Background	p. 242
Assignment of Excitation and Emission Peaks	p. 243
Electron-Phonon Coupling	p. 246
Inhomogeneous Broadening: Spectral and Spatial Aspects	p. 246
Summary of CEES of GaN:Nd	p. 249
Application of CEES to Europium in GaN and AlGaN	p. 250
Introduction	p. 250
Energetic Fingerprints of Different Sites	p. 251
Electron Phonon Coupling	p. 255
Effect of Growth Conditions	p. 257
Excitation under Non-Resonant Conditions	p. 260
Summary	p. 265
Conclusion	p. 266
Acknowledgements	p. 266
References	p. 267
Excitation Mechanisms of RE Ions in Semiconductors	p. 269
Introduction	p. 270
Excitation Mechanisms	p. 271
Excitation Paths Involving Electron-Hole Pairs	p. 271
Excitation Paths Involving Change of RE Ion Charge	p. 274
Excitation Paths Involving Donor-Acceptor Pairs	p. 278
Energy Transfer Processes	p. 280
RE Excitation Processes in GaN	p. 282
RE Excitation Schemes	p. 282
Isolated RE Ions Versus RE Ions Coupled to Carrier Traps	p. 283
Effective Excitation Cross-Section	p. 288
RE-Related Carrier Trap	p. 294
Conclusion	p. 303
Acknowledgements	p. 305
References	p. 305
High-Temperature Ferromagnetism in the Super-Dilute Magnetic Semiconductor GaN:Gd	p. 309
Introduction	p. 310
Experimental	p. 311
Sample Growth and Structural Characterization	p. 311
Assessment of Electrical and Magnetic Properties	p. 312
Assessment of Optical Properties	p. 313
Basic Structural and Magnetic Properties	p. 314
Gd Incorporation in GaN	p. 314
Magnetic Characteristics	p. 318
Phenomenological Model	p. 323
Optical Properties	p. 326
Magnetic Phases and Anisotropy	p. 331
Magnetic Phases	p. 332
Magnetic Anisotropy	p. 334
Discussion	p. 336
Recent Studies in the Literature	p. 338
Conclusions	p. 339
Acknowledgements	p. 340
References	p. 340
Summary and Prospects for Future Work	p. 343
References	p. 345
Index	p. 347
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