List of Contributors ........................................ xviii
1 Development of the nitride-based UV/DUV LEDs ............... 1
Hiroshi Amano
1.1 Introduction ............................................... 1
1.2 Efficiency limiting process ................................ 4
1.2.1 Internal quantum efficiency ......................... 4
1.2.2 Current injection efficiency ....................... 10
1.2.3 Light extraction efficiency ........................ 14
1.3 Summary ................................................... 14
Acknowledgments ........................................... 14
References ................................................ 15
2 The homoepitaxial challenge: GaN crystals grown at high
pressure for laser diodes and laser diode arrays .......... 18
Izabella Grzegory, Michal Bockowski, Piotr Perlin,
Czeslaw Skierbiszewski, Tadeusz Suski, Marcin Sarzynski,
Stanislaw Krukowski, and Sylwester Porowski
2.1 Introduction .............................................. 18
2.2 Thermodynamics of GaN ..................................... 20
2.2.1 Melting conditions of GaN .......................... 20
2.2.2 High-pressure thermodynamics of GaN: phase
diagrams ........................................... 24
2.3 Crystal growth of GaN ..................................... 29
2.3.1 GaN by HVPE ........................................ 30
2.3.2 High-nitrogen-pressure solution growth of GaN ...... 32
2.3.3 Ammonothermal growth of GaN ........................ 38
2.4 Epitaxy of nitrides on single-crystalline HNPS GaN:
early results ............................................. 41
2.5 Development of nitrides epitaxy by PA MBE ................. 44
2.5.1 Growth conditions for PAMBE ........................ 44
2.5.2 The role of threading dislocations and miscut
angle on surface morphology in low-temperature
PAMBE .............................................. 46
2.5.3 The growth of high-in-content InGaN layers by
PAMBE .............................................. 47
2.5.4 The influence of the growth conditions on the
optical properties of InGaN QWs .................... 49
2.5.5 Optical lasing from InGaN QWs ...................... 52
2.5.6 Laser diodes ....................................... 54
2.6 "Plasmonic" GaN substrates and their use for lasers ....... 58
2.7 Laser diode arrays on laterally patterned substrates ...... 61
2.7.1 Background ......................................... 61
2.7.2 Laser diode arrays on laterally patterned HNPS
GaN substrates ..................................... 64
2.8 High-power lasers and arrays on Ammono and HNPS GaN
substrates ................................................ 67
2.9 Summary and conclusions ................................... 71
Acknowledgments ........................................... 72
References ................................................ 72
3 Epitaxial growth and benefits of GaN on silicon ........... 78
Armin Dadgar and Alois Krost
3.1 Introduction .............................................. 78
3.2 The GaN-on-silicon challenges ............................. 78
3.2.1 Lattice mismatch ................................... 79
3.2.2 Thermal mismatch ................................... 81
3.2.3 Meltback etching ................................... 82
3.2.4 Plastic substrate deformation ...................... 83
3.2.5 Vertical conductivity .............................. 85
3.3 Seed layer growth ......................................... 87
3.4 Stress management ......................................... 89
3.4.1 Stress management by Al(Ga)N layers ................ 90
3.4.2 Selective growth ................................... 95
3.5 Dislocation reduction ..................................... 95
3.6 Light-emitting diodes ..................................... 98
3.7 Electronics .............................................. 102
3.7.1 RF transistors .................................... 103
3.7.2 HV transistors .................................... 103
3.8 Limits of GaN-on-Si MOVPE technology and new
developments ............................................. 106
3.8.1 Limits of GaN-on-Si MOVPE technology .............. 107
3.8.2 New developments .................................. 107
Acknowledgments .......................................... 112
References ............................................... 112
4 The growth of bulk aluminum nitride ...................... 121
Ronny Kirste and Zlatko Sitar
4.1 Introduction ............................................. 121
4.2 Bulk AlN: a pathway to high-quality AlGaN ................ 121
4.3 Growth of AlN crystals ................................... 123
4.3.1 Physical vapor transport .......................... 124
4.3.2 Hydrid vapor phase epitaxy ........................ 126
4.3.3 Solution growth ................................... 128
4.3.4 Seeding of AlN crystal growth ..................... 129
4.4 Properties of state-of-the-art bulk A1N .................. 130
4.4.1 Structural properties ............................. 131
4.4.2 Optical properties and impurities ................. 133
4.5 Applications and devices ................................. 137
4.5.1 Properties of AlN and AlGaN epitaxial layers on
AlN ............................................... 137
4.5.2 Devices on bulk AlN substrates .................... 139
4.6 Outlook ............................................. 141
References ............................................... 142
5 Epitaxial growth of nitride quantum dots ................. 147
André Strittmatter
5.1 Introduction ............................................. 147
5.2 GaN quantum dots ......................................... 148
5.2.1 Molecular beam epitaxy ............................ 148
5.2.2 Metalorganic vapor phase epitaxy .................. 151
5.2.3 Growth on non-polar and semipolar planes .......... 152
5.3 InxGa1-xN quantum dots .................................. 157
5.3.1 Phase separation and In segregation effects ....... 157
5.3.2 Stranski-Krastanow growth mode .................... 159
5.3.3 Spontaneous quantum dot formation in InGaN
layers ............................................ 162
5.3.4 Thermal annealing and surface pre-treatment
methods ........................................... 164
5.3.5 InN quantum dots .................................. 165
5.4 Site-selective growth .................................... 167
5.5 Summary .................................................. 169
References ............................................... 170
6 Properties of InAlN layers nearly lattice-matched to
GaN and their use for photonics and electronics .......... 177
Raphaël Butté, Gatien Cosendey, Lorenzo Lugani, Marlene
Glauser, Antonino Castiglia, Guillaume Perillat-
Merceroz, Jean-François Carlin, and Nicolas Grandjean
6.1 Introduction ............................................. 177
6.2 Growth and structural properties of bulk InAIN layers .... 178
6.2.1 Growth characteristics of InAIN films ............. 178
6.2.2 Structural properties of bulk InAIN layers ........ 181
6.3 Optical and electronic properties of bulk InAIN layers ... 188
6.4 Optical features of GaN/InAlN quantum wells .............. 191
6.5 Nearly lattice-matched InAIN/(Al) GaN distributed
Bragg reflectors ......................................... 192
6.5.1 Growth properties ................................. 192
6.5.2 Optical properties ................................ 195
6.5.3 Applications ...................................... 196
6.6 InAIN cladding layers for edge-emitting lasers ........... 200
6.7 InAlN/GaN high electron mobility transistors ............. 207
6.7.1 Growth of InAlN/GaN high electron mobility
heterostructures .................................. 208
6.7.2 InAlN/GaN HEMTs for high-frequency applications ... 210
6.7.3 Power performance of InAlN/GaN HEMTs .............. 212
6.7.4 Enhancement-mode InAlN/GaN HEMTs .................. 214
6.8 Conclusion ............................................... 216
Acknowledgments .......................................... 217
References ............................................... 217
7 Growth and optical properties of aluminum-rich AlGaN
heterostructures ......................................... 227
Hideto Miyake
7.1 Introduction ............................................. 227
7.2 Growth of Si-doped AlGaN on AIN/sapphire templates ....... 228
7.3 Growth of Si-doped AlGaN/AlGaN multiple-quantum wells .... 232
7.4 Fabrication of AlGaN MQWs for electron-beam target
for deep-ultraviolet light sources ....................... 240
7.5 Conclusions .............................................. 241
Acknowledgments .......................................... 242
References ............................................... 242
8 Optical and structural properties of InGaN light-
emitters on non-polar and semipolar GaN .................. 244
Michael Kneissl and Tim Wernicke
8.1 Spontaneous and piezoelectric polarization in InGaN/GaN
quantum wells on c-plane, semipolar,
and non-polar crystal orientations ....................... 245
8.2 Performance characteristics of violet, blue, and green
(0001) c-plane InGaN quantum well LEDs and laser
diodes ................................................... 248
8.3 Growth of non-polar and semipolar GaN buffer layers
for device applications .................................. 253
8.3.1 Growth of GaN on low-defect bulk GaN substrates ... 253
8.3.2 Growth of GaN on planar heteroepitaxial
substrates ........................................ 255
8.3.3 Strategies for defect reduction for
heteroepitaxially grown GaN ....................... 257
8.4 Growth of InGaN layers and quantum wells on m-plane and
different semipolar surfaces, i.e. (1012), (1011),
(2021), (1122) ........................................... 261
8.4.1 Indium incorporation efficiency for different
surface orientations .............................. 261
8.4.2 Optical properties of non-polar and semipolar
InGaN QWs ......................................... 263
8.5 Performance characteristics of non-polar and semipolar
InGaN QW LEDs ............................................ 266
8.5.1 External quantum efficiencies and emission
wavelength ........................................ 266
8.5.2 Polarization effects and efficiency droop ......... 268
8.6 Performance characteristics of non-polar and semipolar
InGaN QW lasers .......................................... 269
8.6.1 Gain characteristics of InGaN quantum-well
lasers on non-polar and semipolar GaN and
effects of the excitation stripe orientation ...... 269
8.6.2 Fabrication of laser cavities (e.g., etched,
cleaved facets) ................................... 272
8.6.3 State-of-the-art of non-polar and semipolar
InGaN laser diodes ................................ 276
8.7 Summary and outlook ...................................... 279
Acknowledgments .......................................... 279
References ............................................... 279
9 GaN-based single-nanowire devices ........................ 289
Rudeesun Songmuang and Eva Monroy
9.1 Introduction ............................................. 289
9.2 Nanowire synthesis ....................................... 290
9.2.1 Catalyst-induced NW growth ........................ 290
9.2.2 Catalyst-free NW growth ........................... 293
9.3 Energy conversion ........................................ 299
9.3.1 Photoconductive detection ......................... 299
9.3.2 Photovoltaics ..................................... 305
9.3.3 Energy harvesting via piezoelectric effects ....... 306
9.4 Nanoelectronics .......................................... 308
9.4.1 GaN NW field-effect transistors ................... 308
9.4.2 GaN NW single-electron transistors ................ 310
9.4.3 GaN/AlN/AlGaN core-shell NW high-electron-
mobility transistors .............................. 312
9.4.4 GaN/AlN axial-heterostructure resonant tunneling
devices ........................................... 313
9.4.5 GaN/AlN axial-heterostructure single-electron
transistors ....................................... 315
9.5 Sensorics ................................................ 317
9.6 Conclusions .............................................. 321
Acknowledgments .......................................... 321
References ............................................... 321
10 Advanced photonic and nanophotonic devices ............... 330
Jean-Yves Duboz
10.1 Planar microcavities ..................................... 330
10.1.1 Linear regime: basics ............................. 330
10.1.2 Linear regime: results ............................ 332
10.1.3 Non-linear regime: basics ......................... 334
10.1.4 Non-linear regime: results ........................ 338
10.2 Photonic crystal ......................................... 342
10.3 Microdisks ............................................... 349
10.4 Nanowires ................................................ 354
10.5 Conclusion ............................................... 357
References ............................................... 358
11 Nitride-based electron devices for high-power/high-
frequency applications ................................... 366
Yvon Cordier, Tatsuya Fujishima, Bin Lu, Elison
Matioli, and Tomás Palacios
11.1 Relevant GaN properties for electron devices ............. 366
11.2 GaN two-terminal devices ................................. 369
11.2.1 High-breakdown Schottky diodes .................... 369
11.2.2 Bipolar GaN diodes (p-n or p-i-n) ................. 372
11.2.3 Gunn diodes ....................................... 373
11.2.4 Tunnel diodes ..................................... 376
11.3 Bipolar junction transistors and heterojunction bipolar
transistors (BJT and HBT) ................................ 380
11.4 Field-effect transistors ................................. 383
11.4.1 High-frequency GaN-based HEMTs for RF and mixed-
signal applications ............................... 384
11.4.2 Lateral GaN high-voltage power transistors ........ 392
11.4.3 Vertical GaN power transistors .................... 400
11.5 Conclusion ............................................... 406
References ............................................... 406
12 Intersubband transitions in low-dimensional nitrides ..... 414
Maria Tchernycheva and François H. Julien
12.1 Introduction ............................................. 414
12.2 Intersubband transitions in nitride heterostructures:
theoretical aspects ...................................... 415
12.2.1 Effective-mass approximation ...................... 416
12.2.2 Band non-parabolicity ............................. 417
12.2.1 Hartree approximation ............................. 417
12.2.4 Internal electric field ........................... 418
12.2.5 Band bending ...................................... 420
12.2.6 Many-body effects ................................. 421
12.2.7 Optical properties of intersubband transitions .... 424
12.3 Intersubband spectroscopy of nitride quantum wells
and quantum dots ......................................... 426
12.3.1 Near-infrared intersubband absorption in polar
GaN/AlN quantum wells ............................. 426
12.3.2 Intersubband transitions in In-containing
heterostructures .................................. 428
12.3.3 Coupled GaN/AlN quantum wells ..................... 429
12.3.4 Mid-infrared intersubband absorption in AlGaN/
GaN quantum wells ................................. 430
12.3.5 Tuning ISB transitions to the terahertz
frequency domain in polar GaN/AlGaN quantum
wells ............................................. 432
12.3.6 Intersubband transitions in semipolar GaN/AlN
quantum wells ..................................... 434
12.3.7 Intersubband transitions in cubic GaN/Al(Ga)N
quantum wells ..................................... 435
12.3.8 Intersublevel absorption in GaN/AIN quantum dots .. 436
12.4 GaN-based intersubband light modulators .................. 438
12.4.1 All-optical switches .............................. 438
12.4.2 Electro-optical modulators ........................ 440
12.5 GaN-based intersubband photodetectors .................... 445
12.5.1 Quantum well infrared photodetectors .............. 445
12.5.2 Quantum dot infrared photodetectors ............... 446
12.5.3 Quantum cascade photodetectors .................... 447
12.6 GaN-based intersubband light emitters .................... 454
12.6.1 ISB light generation in GaN-based QWs through
non-linear optical processes ...................... 454
12.6.2 Intraband emission of GaN-based quantum dots
via a resonant Raman process ...................... 455
12.6.3 Intersubband luminescent devices .................. 456
12.6.4 Towards THz quantum cascade lasers ................ 457
12.7 Conclusions .............................................. 460
References ............................................... 460
13 The slow light in gallium nitride ........................ 476
Tatiana V. Shubina, Mikhail M. Glazov, Nikolay
A. Gippius, and Bernard Gil
13.1 Introduction ............................................. 476
13.2 Slow light: history and recent studies ................... 477
13.2.1 Group velocity in a medium with optical
dispersion ........................................ 477
13.2.2 Light propagation in semiconductors near
excitonic lines ................................... 479
13.2.3 Electromagnetically induced transparency and
other effects ..................................... 481
13.2.4 Light scattering and diffusion .................... 483
13.3 Two mechanisms of light transfer in GaN: ballistic
and diffusive ............................................ 484
13.3.1 Optical dispersion in a medium with several
resonances of free and bound excitons ............. 484
13.3.2 Diffusive propagation of light and resonant
photon scattering by bound excitons ............... 487
13.4 Time-of-flight spectroscopy of light propagating
through GaN crystals ..................................... 488
13.5 Excitonic parameters of wide-gap semiconductors .......... 493
13.6 Distortion of optical pulse near excitonic resonances .... 497
13.7 Concluding remarks ....................................... 500
References ............................................... 500
14 Nitride devices and their biofunctionalization for
biosensing applications .................................. 505
Csilla Gergely
14.1 Introduction ............................................. 505
14.2 Configurations of nitride devices for sensing ............ 506
14.3 Functionalization of nitrides ............................ 508
14.4 Sensing examples with nitride-based devices .............. 511
References ............................................... 516
15 Heterovalent ternary II-IV-N2 compounds: perspectives
for a new class of wide-band-gap nitrides ................ 519
Walter R.L. Lambrecht and Atchara Punya
15.1 Introduction ............................................. 519
15.2 History and crystal growth ............................... 522
15.3 Crystal structure and symmetry ........................... 525
15.3.1 Symmetry .......................................... 525
15.3.2 Lattice constants ................................. 527
15.4 Thermodynamic stability .................................. 527
15.5 Electronic structure ..................................... 533
15.5.1 Computational methods ............................. 534
15.5.2 Band-structure overview ........................... 537
15.5.3 Effective-mass Hamiltonians ....................... 546
15.6 Lattice dynamics ......................................... 550
15.6.1 Computational method .............................. 550
15.6.2 Vibrational modes at the zone center .............. 554
15.6.3 Phonon dispersions and density of states .......... 558
15.6.4 Infrared spectroscopy ............................. 558
15.6.5 Raman spectroscopy ................................ 561
15.7 Elastic and piezoelectric tensors ........................ 565
15.7.1 Theoretical considerations ........................ 565
15.7.2 Values for nitrides ............................... 567
15.8 Spontaneous polarization ................................. 570
15.9 Optical properties ....................................... 571
15.9.1 Indices of refraction ............................. 571
15.9.2 UV dielectric functions ........................... 572
15.9.3 Non-linear optics ................................. 573
15.10 Defects ................................................. 575
15.11 Outlook ................................................. 577
Acknowledgments .......................................... 578
References ............................................... 578
16 Terahertz emission in polaritonic systems with nitrides .. 586
Oleksandr Kyriienko, Ivan A. Shelykh, and Alexey
V. Kavokin
16.1 Introduction ............................................. 586
16.1.1 Excitons .......................................... 587
16.1.2 Exciton-polaritons ................................ 590
16.2 Polariton-based terahertz emitters ....................... 594
16.2.1 Upper-to-lower polariton transition ............... 594
16.2.2 THz emission by 2p-exciton to 1s-polariton
transition ........................................ 604
16.2.3 Dipolariton THz emission .......................... 611
16.3 Conclusion ............................................... 616
Acknowledgments .......................................... 617
References ............................................... 617
Index ......................................................... 619
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