Materials modification by electronic excitation

Contents......Page 6
Preface......Page 14
1.1 Basic ideas about the localisation of charge and energy......Page 18
1.1.1 The polaron concept......Page 20
1.1.2 Excitation of metals and insulators: What is special about insulators?......Page 23
1.2.1 Excitation by electromagnetic radiation......Page 24
1.2.2 Excitation by electrons......Page 32
1.2.3 Other forms of particle excitation......Page 36
1.2.4 Other forms of excitation......Page 40
1.3.1 Structural issues: Where do crystalline and amorphous materials differ?......Page 42
1.3.2 The varied forms of ‘amorphous’......Page 44
1.3.3 Mesostructure......Page 45
1.4.1 Band structures: General features for crystalline and amorphous solids......Page 48
1.4.2 Approaches to electronic structure......Page 51
1.4.3 Special cases......Page 52
1.4.4 Localising charge......Page 55
1.5 Excitation and excited states......Page 62
1.5.1 Optical excitation......Page 63
1.5.2 Excitation by ionising radiation......Page 65
1.5.3 Excitation at higher energies......Page 66
1.6 Excitation of defects and recovery after excitation......Page 69
2 Energy deposition and redistribution in solids......Page 74
2.1 Interactions of charged particles with solids......Page 75
2.2 Theory of the interaction of charged particles with solids......Page 84
2.3 Issues: Beyond the standard models......Page 88
2.4 Challenges: Non-equilibrium situations......Page 91
2.5 Thermal diffusion: Processes near thermal equilibrium......Page 92
2.5.1 The phenomenology of diffusion rates: The Arrhenius and Meyer–Neldel (compensation) expressions......Page 93
2.5.2 Special cases of diffusion......Page 94
2.6.1 Geminate recombination......Page 96
2.6.2 Rate theory and defect aggregates......Page 98
3.1 Basics of electron–lattice coupling......Page 102
3.2 The configuration coordinate diagram......Page 105
3.2.1 The basic configuration coordinate model......Page 106
3.2.2 Choices of configuration coordinate......Page 107
3.2.3 Simple cases: The F centre......Page 108
3.2.4 Optical transitions......Page 110
3.2.5 Charge transfer transitions......Page 112
3.3 Relaxation energies and defect stability......Page 113
3.3.1 Stability and instability......Page 114
3.3.2 Examples of charge state stability......Page 115
3.3.3 Stability of self-trapped polarons: Strategies......Page 116
3.3.4 Stability of small polarons: Static approaches......Page 118
3.3.5 Stability of small polarons: Microscopic calculation of the relaxation energy......Page 119
3.3.6 Small-polaron formation energy: Energy cycles......Page 122
3.3.7 Specific properties of the self-trapped exciton (STX) state......Page 123
3.4.2 Small polarons and large polarons: Ideas about motion......Page 125
3.4.4 Classical diffusion of ions and other over-the-barrier processes......Page 127
3.4.5 Diffusion of self-trapped carriers......Page 130
3.5.1 Cooling of atomic motion......Page 131
3.5.2 Transitions from one energy surface to another......Page 137
3.5.3 Cooling of electronic excitation: Free carrier states......Page 139
3.5.4 Cooling of electronic excitation: Capture and cooling of bound carrier states......Page 142
3.6.1 Kinetics and dynamics......Page 144
3.6.2 Multiphonon non-radiative transitions......Page 145
3.7.1 Routes to the self-trapped state......Page 149
3.7.3 Solvation of an electron in water......Page 152
3.7.4 Frozen Gaussian methods......Page 153
4.1 Self-trapped carriers in halides......Page 155
4.1.1 Self-trapped electrons......Page 157
4.1.2 Self-trapped holes......Page 158
4.1.3 Relaxation processes of self-trapped holes......Page 162
4.1.4 Extrinsic and perturbed self-trapped holes......Page 166
4.2 Self-trapped carriers in oxides......Page 167
4.3 Self-trapped excitons in halides......Page 169
4.3.1 AgCl......Page 171
4.3.2 Alkali halides with the NaCl structure......Page 172
4.3.3 Other halides......Page 183
4.4.1 Self-trapped excitons in oxides with closed-shell cations......Page 188
4.4.2 Self-trapped excitons of oxides with open-shell cations......Page 197
4.5 Self-trapped excitons in crystalline semiconductors......Page 198
Summary......Page 202
5 Local lattice modification by electronic excitation of halides......Page 204
5.1.1 Adiabatic potential energy surfaces and relaxation channels......Page 205
5.1.2 Experimental evidence for three channels for defect pair formation in alkali halides......Page 210
5.1.3 Branching between the relaxation channels from exciton to defect pair......Page 212
5.1.4 Thermal conversion from self-trapped exciton to defect pair......Page 218
5.1.5 Other materials in which the excitonic mechanism is effective......Page 222
5.2.1 Defect formation from interacting excitons......Page 224
5.2.2 Defect generation by two-hole localisation......Page 225
5.2.3 The photographic process in silver halides......Page 226
5.2.4 Photochromic and photosensitive glasses......Page 231
5.2.5 Creation of defect pairs in the cation sublattice......Page 232
5.3 Defects created by ionising radiation......Page 233
5.3.1 Defect pairs created at low temperatures......Page 234
5.3.2 Stabilisation of interstitials......Page 236
Summary......Page 240
6.1.1 Oxides and halides: Basics and similarities......Page 241
6.1.2 Self-trapping in oxides......Page 242
6.1.3 Charge transfer and colour......Page 243
6.1.4 Non-linear processes and negative U......Page 245
6.1.5 Amorphisation......Page 246
6.2.1 Damage and degradation......Page 247
6.2.2 Amorphisation by electron beams......Page 249
6.2.3 Transient defects......Page 250
6.3 Electrical breakdown and related phenomena......Page 251
6.3.1 Metal–insulator transitions in oxide films......Page 252
6.3.2 Electrical breakdown in simple ceramic oxides, like MgO and alumina......Page 254
6.3.3 Breakdown in the oxide on silicon......Page 255
6.3.4 Radiation-induced electrical degradation......Page 259
Summary......Page 261
7.1 General comparisons: Switching between states and motion......Page 262
7.2.1 Characteristics of enhanced diffusion......Page 264
7.2.2 Routes to enhanced diffusion......Page 267
7.2.3 Understanding enhanced diffusion......Page 269
7.3 Local heating models (‘hot-spot’ or ‘phonon-kick’ mechanisms)......Page 270
7.3.2 The model of Masri and Stoneham......Page 271
7.3.3 The model of Sumi......Page 272
7.3.4 Other general issues......Page 273
7.4 Local excitation models, including the Bourgoin–Corbett mechanism......Page 276
7.4.1 Case I: Energy extrema at the same site......Page 277
7.4.2 Case II: Energy surfaces with extrema at different sites......Page 278
7.4.3 The Bourgoin–Corbett model......Page 280
7.4.4 Analogous systems: Metastability and reorientation......Page 281
7.5 How can the mechanisms be distinguished from each other?......Page 283
7.5.2 Reasonableness arguments......Page 284
7.5.3 Are charge state changes possible and significant?......Page 285
7.6.1 Competing processes: Isotope effects in electrical isolation......Page 286
7.6.2 Dislocation growth and motion......Page 287
7.6.3 Enhanced oxidation......Page 290
Summary......Page 291
8 Local lattice modification of amorphous materials by electronic excitation......Page 292
8.1.1 The optical absorption edge......Page 297
8.1.2 Motion of electrons and holes......Page 299
8.2 Optical absorption and luminescence......Page 301
8.2.1 Amorphous silicas: a-SiO[sub(2)]......Page 304
8.2.2 Chalcogenides......Page 309
8.2.3 Diamond-like carbon (a-C:H; DLC) and amorphous silicon (a-Si:H)......Page 311
8.3 Defect formation......Page 317
8.3.1 Amorphous silicas: a-SiO[sub(2)]......Page 318
8.3.2 Chalcogenides......Page 326
8.3.3 Amorphous silicon: a-Si:H......Page 328
8.4 Photo-induced structural changes: Photodarkening......Page 330
8.5.1 Ion-induced crystallisation and amorphisation of silicate glasses......Page 336
Appendix: Basic defects in glasses......Page 338
Summary......Page 341
9.1 Energy absorption near surfaces......Page 342
9.1.1 Perfect surfaces......Page 344
9.1.2 Near-surface defects......Page 345
9.1.3 Surface defects......Page 347
9.1.5 Surface topography......Page 350
9.1.7 Surface excitation following bulk excitation......Page 352
9.1.8 Exoelectron emission......Page 354
9.1.10 Local lattice modification on surfaces......Page 356
9.1.12 Laser excitation of surfaces......Page 358
9.2.1 Excitons and holes on surfaces......Page 360
9.2.2 Mechanisms for the sputtering of alkali halides......Page 362
9.2.3 Sputtering of other halides......Page 377
9.3.1 Emissions by core excitation......Page 381
9.3.2 Surface modification of quartz......Page 382
9.3.3 Laser excitation of other oxides......Page 384
9.4 Semiconductors......Page 385
9.4.1 Atomic emissions from semiconductors by laser irradiation......Page 386
9.4.2 STM observation of photo-induced atomic emission from Si surfaces......Page 390
9.4.3 Photo-induced surface modification of compound semiconductors......Page 391
9.4.4 Scanning probe microscopy removal of atoms......Page 392
Summary......Page 395
10 Interface reactions induced by electronic excitation......Page 396
10.1.1 Interface atomic structures......Page 397
10.1.2 Interfaces between crystalline and non-crystalline solids......Page 400
10.2.1 Energy deposition by elastic encounters......Page 404
10.2.2 Energy deposition by electronic excitation......Page 405
10.3.1 Luminescence at interfaces......Page 406
10.3.2 Modification of interface structures......Page 407
10.4.1 Mixing by elastic encounters......Page 409
10.4.2 Mixing by electronic excitation......Page 410
10.5.1 Phenomenology......Page 411
10.5.2 Summary of existing data......Page 412
10.5.3 How to interpret radiation-enhanced adhesion......Page 414
10.5.4 Related phenomena: Anodic bonding......Page 416
10.6 Oxidation and chemical reactions at interfaces......Page 417
10.7 Amorphisation and recrystallisation......Page 421
Summary......Page 423
11.1 Introduction......Page 424
11.1.1 Thermal models of modification......Page 426
11.1.2 Non-uniform damage......Page 427
11.1.3 The early stages of energy deposition......Page 428
11.1.4 Processing by high-intensity excitation......Page 429
11.1.5 Sputtering by ion beams......Page 430
11.2 Laser annealing......Page 432
11.3 Laser damage......Page 435
11.4 Laser ablation......Page 439
11.4.1 Energy absorption and transfer......Page 440
11.4.2 Gaps less than the laser photon energy......Page 442
11.4.3 Gaps in excess of the laser photon energy: Effects of pre-existing defects......Page 443
11.4.4 Mesoscopic modelling of laser ablation......Page 446
11.5.1 Lithography by electron beams......Page 448
11.5.2 Nanolithography of MgO and other oxides......Page 450
11.6 Irradiation with heavy ions......Page 452
11.6.1 Processes taking place near GeV heavy-ion paths in the first few femtoseconds......Page 453
11.6.2 Registration of heavy-ion tracks......Page 455
11.6.3 Effects of heavy-ion irradiation on surfaces and interfaces......Page 456
11.6.4 The Coulomb explosion model......Page 457
11.6.6 Excitonic model......Page 458
Summary......Page 460
12.1 Aims of materials modification......Page 461
12.2 Modifying surface and near-surface regions......Page 465
12.3 Modifying the bulk solid......Page 470
12.4 Damage and deterioration......Page 475
12.5 Changing rates and altering processes......Page 479
12.6 Concluding comments......Page 481
Summary......Page 483
References......Page 484
A......Page 526
C......Page 527
D......Page 528
E......Page 529
H......Page 530
L......Page 531
M......Page 532
P......Page 533
S......Page 534
T......Page 536
Z......Page 537