Copyright 2004 by Marcel Dekker, Inc. All Rights Reserved.

More documents

Recommendations

Info

Taken together, the hexagonal lattice structure, crystal shape asymmetry,and the electron–hole-exchange interaction split the original ‘‘spherical’’eightfold degenerate exciton into five levels. The levels are labeled by themagnitude of the exciton total angular momentum projection, F = M + s z :one level with F = F2, two with F = F1, and two with F = 0. The levelenergies, e jFj , are determined by solving the secular equation det(Eˆ e jFj ) = 0,where the matrix Eˆ consists of matrix elements of the asymmetry perturbationsand the exchange interaction, Hˆexch, taken between the exciton wavefunctions C a,M (r e , r h ) = w a (r e )w M (r h ):z; 3=2 z; 1=2 z; 1=2 z; 3=2 #; 3=2 #; 1=2 #; 1=2 #; 3=2z; 3=23g2z; 1=2 0D2g20 0 0 0 0 0 0D2pffiffiffi0 0 i 3 g 0 0 0gz; 1=2 0 02 þ D 0 0 i2g 0 023g Dpffiffiffiz; 3=2 0 0 00 0 i 3 g 02 2pffiffi3g D#; 3=2 0 i 3 g 0 0 0 0 02 2g#; 1=2 0 0 i2g 0 02 þ D 0 02pffiffiffig#; 1=2 0 0 0 i 3 g 0 02 þ D 023g#; 3=2 0 0 0 0 0 0 02D2ð14Þwhere g = (a ex /a) 3 tx ST v(b), and the dimensionless function v(b) is writtenin terms of the electron and hole radial wave functions:vðbÞ ¼ 1 Z aa 2 dr sin 2 ðpr=aÞ½R 2 06ðrÞ þ 0:2R2 2 ðrÞŠ0ð15ÞThe dependence of v on the parameter b is shown in Fig. 1d.Solution of the secular equation yields five exciton levels. The energyof the exciton with total angular momentum projection jFj = 2 and itsdependence on the crystal size is given by [3]e 2 ¼3g2D2ð16ÞCopyright 2004 by Marcel Dekker, Inc. All Rights Reserved.
The respective wave functions areC 2 ðr e ; r h Þ ¼ C #; 3=2 ðr e ; r h Þ ð17ÞC 2 ðr e ; r h Þ ¼ C z;3=2 ðr e ; r h ÞThe energies and size dependences of the two levels, each with total momentumprojection jFj = 1, are given by [3]sffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffie U;L1¼ g 2 F ð2g DÞ 2þ 3g42ð18Þwhere U and L correspond to the upper (‘‘+’’) or lower (‘‘ ’’) signs,respectively. We denote these states by F1 U and F1 L , respectively (i.e., theupper and lower state with projection F = F1). The corresponding wavefunctions for the states with F = +1 are*C U 1 ðr e; r h Þ ¼iC þ C z;1=2 ðr e ; r h Þ þ C C #;3=2 ðr e ; r h ÞC L 1 ðr e; r h Þ ¼ þiC C z;1=2 ðr e ; r h Þ þ C þ C #;3=2 ðr e ; r h Þð19Þwhereas for the states with F =1, the wave functions areC U 1 ðr e; r h Þ ¼ iC C z; 3=2 ðr e ; r h Þ C þ C #; 1=2 ðr e ; r h ÞC L 1 ðr e; r h Þ ¼ þiC þ C z; 3=2 ðr e ; r h Þ þ C C #; 1=2 ðr e ; r h Þð20ÞwhereC F ¼pffiffiffiffiffiffiffiffiffiffiffiffiffi! 1=2f 2 dFfpffiffiffiffiffiffiffiffiffiffiffiffiffið21Þ2 f 2 df = ( 2g + D)/2, and d = 3g 2 . The size-dependent energies of the two F = 0exciton levels are given bye U;L0¼ g 2 þ D F2g ð22Þ2(we denote the two F = 0 states by 0 U and 0 L ), with corresponding wavefunctions0ðr e ; r h Þ ¼ p 1 ffiffi ½biC z; 1=2 ðr e ; r h Þ þ C #;1=2 ðr e ; r h ÞŠ ð23Þ2C U;L* There are misprints in the function definitions of Eqs. (19) and (20) of Ref. 3.Copyright 2004 by Marcel Dekker, Inc. All Rights Reserved.
Page 1:
Copyright 2004 by Marcel Dekker, In
Page 4 and 5:
Page 6 and 7:
Page 8 and 9:
This book covers several topics of
Page 10 and 11:
esult, some exciting topics were no
Page 12 and 13:
3. Fine Structure and Polarization
Page 14 and 15:
9. III-V Quantum Dots and Quantum D
Page 16 and 17:
ContributorsUri BaninThe Hebrew Uni
Page 18 and 19:
1‘‘Soft’’ Chemical Synthesi
Page 20 and 21:
structure of energy states leads to
Page 22 and 23:
growth can proceed by Ostwald ripen
Page 24 and 25:
Figure 3 Transmission electron micr
Page 26 and 27:
Figure 4 Temporal evolution of the
Page 28 and 29:
No. 26, are f85% (Fig. 6) [21]. Alt
Page 30 and 31:
tion spectra and broad PL spectra.
Page 32 and 33:
ing surface-to-volume ratio with di
Page 34 and 35:
Figure 8 Photoluminescence spectra
Page 36 and 37:
lattice mismatch. Such a large latt
Page 38 and 39:
match between InAs and ZnS of f11%.
Page 40 and 41:
successfully repeated for up to thr
Page 42 and 43:
Under a different growth regime, on
Page 44 and 45:
Figure 14 Atomic model of the CdSe
Page 46 and 47:
‘‘Teardrop-shaped’’ particl
Page 48 and 49:
Figure 17 High-resolution TEMs of C
Page 50 and 51:
allows isolation of tetrapods in f8
Page 52 and 53:
ligand concentrations yield a reduc
Page 54 and 55:
een determined and quantitatively c
Page 56 and 57:
tion volumes were also shown to be
Page 58 and 59:
synthesis temperatures of z400jC ar
Page 60 and 61:
Figure 23 (a) Photoluminescence spe
Page 62 and 63:
levels (fV1 Mn per NQD). Despite in
Page 64 and 65:
Figure 25 X-ray diffraction pattern
Page 66 and 67:
Figure 27 Transmission electron mic
Page 68 and 69:
An additional factor that strongly
Page 70 and 71:
Figure 30 (a,b) Schematics illustra
Page 72 and 73:
Slow, controlled precipitation of h
Page 74 and 75:
Figure 34 Schematic illustrating th
Page 76 and 77: Figure 36 Transmission electron mic
Page 78 and 79: achieving biological compatibility
Page 80 and 81: 47. Yu H.; Gibbons P.C.; Kelton K.F
Page 82 and 83: 2Electronic Structure inSemiconduct
Page 84 and 85: Figure 2 (a) Simple model of a nano
Page 88 and 89: electron and hole to be treated as
Page 90 and 91: independently, Eq. (13) is commonly
Page 92: a better description of the bulk ba
Page 95 and 96: investigated. For optical experimen
Page 97 and 98: Figure 4 (a) Absorption (solid line
Page 99 and 100: Figure 6 Normalized PLE scans for s
Page 101 and 102: Figure 8 A simplistic model for des
Page 103 and 104: Figure 10 Theoretically predicted p
Page 105 and 106: Figure 12 Schematics depicting the
Page 107 and 108: Figure 14 Calculated band-edge exci
Page 109 and 110: Figure 15 Absorption (solid line) a
Page 111 and 112: Figure 18 (a) Calculated band-edge
Page 113 and 114: IV.BEYOND CdSeA. Indium Arsenide Na
Page 115 and 116: the six-band Luttinger Hamiltonian.
Page 117 and 118: 11. Norris, D.J.; Efros, Al.L.; Ros
Page 119 and 120: 69. Gaponenko, S.V.; Woggon, U.; Sa
Page 121 and 122: formation of a long-lived dark exci
Page 123 and 124: where the constant A is determined
Page 125: In crystals for which the function
Page 129 and 130: passive, as was shown in Ref. 12. T
Page 131 and 132: square of the matrix element of the
Page 133 and 134: where e F = e F ieV and e F F = e x
Page 135 and 136: see that for all nanocrystal shapes
Page 137 and 138: optical recombination of the excito
Page 139 and 140: B. Recombination of the Dark Excito
Page 141 and 142: where x = cos h and f = l B g e H/3
Page 143 and 144: The theory of the polarization memo
Page 145 and 146: Figure 7 The size dependence of the
Page 147 and 148: state would have an infinite lifeti
Page 149 and 150: crystal axis [see Eq. (40)]. As a r
Page 151 and 152: time of the exciton momentum relaxa
Page 153 and 154: One must also account for the influ
Page 155 and 156: observed in one of the first studie
Page 157 and 158: REFERENCES1. Bawendi, M.G.; Wilson,
Page 159 and 160: 4Intraband Spectroscopyand Dynamics
Page 161 and 162: The solid line in Fig. 1 shows the
Page 163 and 164: Figure 2 FTIR spectra of n-type CdS
Page 165 and 166: of the center frequency. The experi
Page 167 and 168: limit given by radiative relaxation
Page 169 and 170: from a long lifetime due to the pho
Page 171 and 172: are two natural approaches to study
Page 173 and 174: 32. Inoshita, T.; Sakaki, H. Physic
Page 175 and 176: continuous spectral tunability over
Page 177 and 178:
function and envelope function mome
Page 179 and 180:
ottleneck’’ [14,28]. Further re
Page 181 and 182:
in NQDs is dominated by nonphonon e
Page 183 and 184:
Figure 4 Dynamics of the IR postpum
Page 185 and 186:
Figure 5 (a) Time-resolved PL spect
Page 187 and 188:
Figure 6 (a) The time delay of the
Page 189 and 190:
and due to Auger-type e-h interacti
Page 191 and 192:
Figure 9 Dynamics of the 1S bleachi
Page 193 and 194:
significantly greater than the fast
Page 195 and 196:
Figure 11 (a) Pump-intensity-depend
Page 197 and 198:
NQD size. For small NQD sizes (R =
Page 199 and 200:
Figure 14 Nonlinear absorption/gain
Page 201 and 202:
sorption change associated with a s
Page 203 and 204:
where n h em is the hole ‘‘emit
Page 205 and 206:
ultrafast (subpicosecond to picosec
Page 207 and 208:
Figure 18 Schematic of transitions
Page 209 and 210:
Figure 19 Dynamics of pump-induced
Page 211 and 212:
where n i (i=1, 2 . . . , N ) is th
Page 213 and 214:
Figure 21 (a) Two-e-h-pair (biexcit
Page 215 and 216:
the volume fraction (filling factor
Page 217 and 218:
intensity dependence of this peak (
Page 219 and 220:
Page 221 and 222:
can contribute to the saturation of
Page 223 and 224:
Page 225 and 226:
coupling between ‘‘volume’’
Page 227 and 228:
numerous discussions on the photoph
Page 229 and 230:
53. Kang, K.; Kepner, A.; Gaponenko
Page 231 and 232:
the ‘‘on-off ’’ emission in
Page 233 and 234:
parallel form of data acquisition i
Page 235 and 236:
Figure 3 (a) Spectral time trace of
Page 237 and 238:
transition energies. In fact, these
Page 239 and 240:
distribution (dark line) does not d
Page 241 and 242:
exposure to only room light. In our
Page 243 and 244:
statistics for the off times are in
Page 245 and 246:
230Shimizu and BawendiCopyright 200
Page 247 and 248:
Figure 10 (a) Time trace of a CdSe(
Page 249 and 250:
and excited QD core states to fluct
Page 251 and 252:
arrows indicate the on-time truncat
Page 253 and 254:
W. K. Woo and V. C. Sundar for assi
Page 255 and 256:
size allows the electron affinity a
Page 257 and 258:
II.THEORY OF ELECTRON TRANSFER BETW
Page 259 and 260:
For the specific case of charge tra
Page 261 and 262:
dominates, the mobility is often fi
Page 263 and 264:
where the constant A and the temper
Page 265 and 266:
components of modulation which are
Page 267 and 268:
nanocrystals [41], understanding ph
Page 269 and 270:
and ionization potential through tw
Page 271 and 272:
quantum dots. Furthermore, because
Page 273 and 274:
For many applications, a host mater
Page 275 and 276:
form blends with morphologies that
Page 277 and 278:
Figure 11 Photoluminescence efficie
Page 279 and 280:
Figure 12 (a) Room-temperature PIA
Page 281 and 282:
discussed briefly in Section IV. Ch
Page 283 and 284:
dithiolates to thiol-terminated DNA
Page 285 and 286:
Films of passivated CdSe nanocrysta
Page 287 and 288:
Figure 16 Photocurrent action spect
Page 289 and 290:
decay with stretched exponential ki
Page 291 and 292:
siderably larger than might be esti
Page 293 and 294:
dispersing CdSe nanocrystal chromop
Page 295 and 296:
memory and charge storage effects [
Page 297 and 298:
all) of the optically excited elect
Page 299 and 300:
composites of nanocrystals and conj
Page 301 and 302:
55. Asbury, J.B.; Hao, E.C.; Wang,
Page 303 and 304:
108. Morgan, N.Y.; Leatherdale, C.A
Page 305 and 306:
The approaches to fabrication of se
Page 307 and 308:
Figure 1 Experimental realization o
Page 309 and 310:
Due to this voltage division, the m
Page 311 and 312:
Figure 3 Simulated tunneling spectr
Page 313 and 314:
electron charging. In both positive
Page 315 and 316:
Figure 5 shows the typical features
Page 317 and 318:
Figure 7 Map of levels for InAs nan
Page 319 and 320:
Figure 8 Scanning electron microsco
Page 321 and 322:
D CB = 0.31 eV is thus obtained. On
Page 323 and 324:
Figure 11 Correlation of optical an
Page 325 and 326:
atomistic approach based on pseudop
Page 327 and 328:
charging indicated that the tunneli
Page 329 and 330:
capacitance values were also kept t
Page 331 and 332:
could not be detected in the QD/DT/
Page 333 and 334:
Figure 18 Tunneling conductanceF sp
Page 335 and 336:
data in the inset of Fig. 19 repres
Page 337 and 338:
corresponding to the s-like wave fu
Page 339 and 340:
7. Grabert, H.; Devoret, M.H., Eds.
Page 341 and 342:
66. Su, B.; Goldman, V.J.; Cunningh
Page 343 and 344:
dimensional confinement are created
Page 345 and 346:
Figure 1 Transmission electron micr
Page 347 and 348:
The room-temperature absorption and
Page 349 and 350:
narrower in samples with larger mea
Page 351 and 352:
GaInP 2 QDs from a plot of the squa
Page 353 and 354:
crystal, indicating lattice-matched
Page 355 and 356:
Figure 5 Evolution of Stranski-Kras
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
C. Efficient Anti-Stokes Photolumin
Page 363 and 364:
Because HF treatment has been shown
Page 365 and 366:
Page 367 and 368:
intensity of the PL when it is on a
Page 369 and 370:
eV stems from recombining carriers
Page 371 and 372:
Figure 16 Model to explain two-colo
Page 373 and 374:
although this term is not rigorousl
Page 375 and 376:
10 ps (about an order of magnitude
Page 377 and 378:
electron relaxation is inhibited an
Page 379 and 380:
Page 381 and 382:
QDs, the nature of the QD capping s
Page 383 and 384:
QD solution. For an interdot distan
Page 385 and 386:
emission spectra of the two individ
Page 387 and 388:
Figure 23 Change of the PL intensit
Page 389 and 390:
(viz. the absorbed light intensity)
Page 391 and 392:
Figure 25Impact ionization in QDs.m
Page 393 and 394:
prevent electron-hole recombination
Page 395 and 396:
36. Miller, R.D.J.; McLendon, G.; N
Page 397 and 398:
91. Vurgaftman, I.; Singh, J. Appl.
Page 399 and 400:
139. Mićić, O.I.; Ahrenkiel, S.P.
Page 401 and 402:
10Synthesis and Fabrication of Meta
Page 403 and 404:
Figure 2 (A-C) Progression of HR-TE
Page 405 and 406:
Figure 3 Schematic for gold nanocry
Page 407 and 408:
Nanocrystal growth can occur by two
Page 409 and 410:
on the other hand, provide an ensem
Page 411 and 412:
Figure 6 (a) SAXS patterns for disp
Page 413 and 414:
Figure 8 The gold nanocrystal film
Page 415 and 416:
of the stabilizing ligand, and the
Page 417 and 418:
successfully modeled the 2D island
Page 419 and 420:
2. Steric Stabilization and a Soft
Page 421 and 422:
are fully extended. Moving away fro
Page 423 and 424:
Figure 11 High-resolution SEM image
Page 425 and 426:
Figure 13 (A) Transmission electron
Page 427 and 428:
function of the density of localize
Page 429 and 430:
Figure 15 High-resolution SEM image
Page 431 and 432:
thiol-capped nanocrystals [2]. The
Page 433 and 434:
41. Ackerson, B.J. Nature 1993, 365
Page 435 and 436:
with the effect of the particle com
Page 437 and 438:
Figure 1a shows the surface plasmon
Page 439 and 440:
Figure 2 (a) Ultraviolet-visible ab
Page 441 and 442:
agents [34]. The short-wavelength b
Page 443 and 444:
Figure 4 (a) Plot of the plasmon ab
Page 445 and 446:
the framework of traditional Mie’
Page 447 and 448:
show that effects due to the surrou
Page 449 and 450:
is located at the position of the g
Page 451 and 452:
Page 453 and 454:
Figure 8 Ultraviolet-visible absorp
Page 455 and 456:
laser pulses while being mixed in t
Page 457 and 458:
Figure 10 shows HR-TEM images of go
Page 459 and 460:
Page 461 and 462:
final irradiation product. At the s
Page 463 and 464:
following the laser excitation appe
Page 465 and 466:
36. Papavassiliou, G.C. Prog. Solid
Page 467 and 468:
particles to expand. Because the he
Page 469 and 470:
was frequency doubled in a 1-mm B-
Page 471 and 472:
Figure 2 Frequency of the acoustic
Page 473 and 474:
Figure 3 Change in radius (DR/R) ve
Page 475 and 476:
In this model, the electrons couple
Page 477 and 478:
Figure 5 Transient bleach data for
Page 479 and 480:
Figure 7 (a) Transient bleach data
Page 481 and 482:
that the particles with >80% Au hav
Page 483 and 484:
3. Del Fatti, N.; Valle´e, F.; Fly
show all

Copyright 2004 by Marcel Dekker, Inc. All Rights Reserved.

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?