Introduction to Nanotechnology

More documents

Recommendations

Info

5.4. CARBON NANOTUBES 11 9 investigate the electronic structure of carbon nanotubes. In this measurement the position of the STM tip is fixed above the nanotube, and the voltage V between the tip and the sample is swept while the tunneling current Z is monitored. The measured conductance G = I/ Vis a direct measure of the local electronic density of states. The density of states, discussed in more detail in Chapter 2, is a measure of how close together the energy levels are to each other. Figure 5.16 gives the STM data plotted as the differential conductance, which is (dI/dV',)/(I/ V',), versus the applied voltage between the tip and carbon nanotube. The data show clearly the energy gap in materials at voltages where very little current is observed. The voltage width of this region measures the gap, which for the semiconducting material shown on the bottom of Fig. 5.16 is 0.7 eV W 0 z s I I I I I VOLTAGE (V) VOLTAGE (V) Figure 5.16. Plot of differential conductance (d//dV)(// V) obtained from scanning tunneling microscope measurements of the tunneling current of metallic (top figure) and semiconducting (bottom figure) nanotubes. [With permission from C. Dekker, fhys. Today 22 (May 1999).]
120 CARBONNANOSTRUCTURES At higher energies sharp peaks are observed in the density of states, referred to as van Hove singularities, and are characteristic of low-dimensional conducting materials. The peaks occur at the bottom and top of a number of subbands. As we have discussed earlier, electrons in the quantum theory can be viewed as waves. If the electron wavelength is not a multiple of the circumference of the tube, it will destructively interfere with itself, and therefore only electron wavelengths that are integer multiples of the circumference of the tubes are allowed. This severely limits the number of energy states available for conduction around the cylinder. The dominant remaining conduction path is along the axis of the tubes, making carbon nanotubes function as one-dimensional quantum wires. A more detailed discussion of quantum wires is presented later, in Chapter 9. The electronic states of the tubes do not form a single wide electronic energy band, but instead split into one- dimensional subbands that are evident in the data in Fig. 5.16. As we will see later, these states can be modeled by a potential well having a depth equal to the length of the nanotube. Electron transport has been measured on individual single-walled carbon nanotubes. The measurements at a millikelvin (T=O.OOl K) on a single metallic nanotube lying across two metal electrodes show steplike features in the current- voltage measurements, as seen in Fig. 5.17. The steps occur at voltages which depend on the voltage applied to a third electrode that is electrostatically coupled to the nanotube. This resembles a field effect transistor made from a carbon nanotube, which is discussed below and illustrated in Fig. 5.2 1. The step like features in the I-V curve are due to single-electron tunneling and resonant tunneling through single molecular orbitals. Single electron tunneling occurs when the capacitance of the nanotube is so small that adding a single electron requires an electrostatic charging Figure 5.17. Plot of electron transport for two different gate voltages through a single metallic carbon nanotube showing steps in the /-V curves. [With permission from C. Dekker, Phys. Today22 (May 1999).]
Page 2 and 3:
INTRODUCTION TO NANOTECHNOLOGY Char
Page 4 and 5:
CONTENTS Preface xi 1 Introduction
Page 6 and 7:
5.2 Carbon Molecules 103 5.2.1 Natu
Page 8 and 9:
9.4 Excitons 244 9.5 Single-Electro
Page 10 and 11:
PREFACE In recent years nanotechnol
Page 12 and 13:
INTRODUCTION The prefix nano in the
Page 14 and 15:
INTRODUCTION 3 he recognized the ex
Page 16 and 17:
1000 (I) a 900 4 800 a 900 I 6 700
Page 18 and 19:
INTRODUCTION 7 developed before the
Page 20 and 21:
2.1. STRUCTURE 9 mechanics, the res
Page 22 and 23:
X T 2.1. STRUCTURE 11 Figure 2.4. C
Page 24 and 25:
2.1. STRUCTURE 13 Figure 2.6. Thirt
Page 26 and 27:
Sodium Nanoparticle Na, Magic Numbe
Page 28 and 29:
2.1. STRUCTURE 17 of the large anio
Page 30 and 31:
2.1. STRUCTURE 19 other, and high-f
Page 32 and 33:
2.2. ENERGY BANDS 21 Conduction Ban
Page 34 and 35:
2.2. ENERGY BANDS 23 Figure 2.13. S
Page 36 and 37:
2.2. ENERGYBANDS 25 band at point T
Page 38 and 39:
A X ' Wavevector A Si c z 2.2. ENER
Page 40 and 41:
2.2. ENERGY BANDS 29 bands of Figs.
Page 42 and 43:
2.3. LOCALIZED PARTICLES 31 add ele
Page 44 and 45:
1 meV 10 meV 100 meV FJ E W 1 eV 10
Page 46 and 47:
3 METHODS OF MEASURING PROPERTIES 3
Page 48 and 49:
3.2. STRUCTURE 37 Table 3.1. Crysta
Page 50 and 51:
3.2. STRUCTURE 39 Figure 3.2. Two-d
Page 52 and 53:
3.2. STRUCTURE 41 The widths of the
Page 55 and 56:
44 METHODS OF MEASURING PROPERTIES
Page 57 and 58:
Page 59 and 60:
Page 62 and 63:
3.3. MICROSCOPY 51 types of transit
Page 64 and 65:
3.3. MICROSCOPY 53 Actual diverging
Page 66 and 67:
Tunneling current Tunneling current
Page 68 and 69:
3.3. MrCAOSCOPY 57 and the latter m
Page 70 and 71:
3.4. SPECTROSCOPY 59 From Eq. (3.8)
Page 72 and 73:
1 Average Panicle FWHM Size (nm) in
Page 74 and 75:
CdSe colloidal NCs a = 1.2 nrn 3.4.
Page 76 and 77:
El X-RAY TUBE 8000 - A 6000 - 4000
Page 78 and 79:
2 N I w 3.0 2.5 2.0 1.5 1 .o 0.5 3.
Page 80 and 81: i 3.4. SPECTROSCOPY 69 NMR involves
Page 82 and 83: T=220K - 2G H FURTHER READING 71 Fi
Page 84 and 85: NUMBER OF ATOMS RADIUS (nm) 1 10 1
Page 86 and 87: I L 7 3 5 7 9 11 13 15 17 NUMBER OF
Page 88 and 89: JELLIUM MODEL OF CLUSTERS ATOMS CLU
Page 90 and 91: 1.02 { 1.01 - 1 - 0.99 - 4.2. METAL
Page 92 and 93: 4.2. METAL NANOCLUSTERS 81 Figure 4
Page 94 and 95: 4.2. METAL NANOCLUSTERS 83 Figure 4
Page 96 and 97: -0 100 200 300 400 500 600 MASSICHA
Page 98 and 99: a 42. METAL NANOCLUSTERS 87 Figure
Page 100 and 101: . . . .. . - . D 111111111111111111
Page 102 and 103: 3 4 2.5 0 cn g 2 0 z d 1.5 t a 9 1
Page 104 and 105: 4.3. SEMICONDUCTING NANOPARTICLES 9
Page 106 and 107: 4.4. RARE GAS AND MOLECULAR CLUSTER
Page 108 and 109: 4.5. METHODS OF SYNTHESIS 97 d Figu
Page 110 and 111: 4.5. METHODS OF SYNTHESIS 99 isopro
Page 112 and 113: PULSED LASER BEAM 1 1 1 1 1 I ROTAT
Page 114 and 115: 5.1. INTRODUCTION CARBON NANOSTRUCT
Page 116 and 117: 5.2. CARBON MOLECULES 105 methane d
Page 118 and 119: 5.3. CARBON CLUSTERS 107 -0 20 40 6
Page 120 and 121: PHOTON ENERGY (electron volts) 5.3.
Page 122 and 123: Figure 5.6. Structure of the CEO fu
Page 124 and 125: 1 30 0 14.1 14.2 14.3 14.4 14.5 LAT
Page 126 and 127: (c) 5.4. CARBON NANOTUBES 115 Figur
Page 128 and 129: 5.4. CARBON NANOTUBES 1 17 The mech
Page 132 and 133: 5.4. CARBON NANOTUBES 121 energy gr
Page 134 and 135: 5.4. CARBON NANOTUBES 123 stretch c
Page 136 and 137: 5.5. APPLICATIONS OF CARBON NANOTUB
Page 140 and 141: - v) 450 : 400 3 350 1 300 : 5 250
Page 144 and 145: BULK NANOSTRUCTURED MATERIALS In th
Page 146 and 147: h 8 0 6.1. SOLID DISORDERED NANOSTR
Page 148 and 149: 6.1. SOLID DISORDERED NANOSTRUCTURE
Page 164 and 165: 6.2. NANOSTRUCTURED CRYSTALS 153 qu
Page 166: 6.2. NANOSTRUCTURED CRYSTALS 155 Fi
Page 169 and 170: 158 BULK NANOSTRUCTURED MATERIALS 6
Page 171 and 172: 160 BULK NANOSTRUCTURED MATERIALS w
Page 173 and 174: 162 BULK NANOSTRUCTURED MATERIALS 0
Page 175 and 176: 164 BULK NANOSTRUCTURED MATERIALS n
Page 177 and 178: 166 NANOSTRUCTURED FERROMAGNETISM f
Page 179 and 180: 168 NANOSTRUCTURED FERROMAGNETISM i
Page 181 and 182:
170 NANOSTRUCTURED FERROMAGNETISM M
Page 183 and 184:
172 NANOSTRUCTURED FERROMAGNETISM h
Page 185 and 186:
174 NANOSTRUCTURED FERROMAGNETISM d
Page 187 and 188:
176 NANOSTRUCTURED FERROMAGNETISM o
Page 190 and 191:
4 h $ 3 7.5. NANOCARBON FERROMAGNET
Page 192 and 193:
7.6. GIANT AND COLOSSAL MAGNETORESI
Page 194 and 195:
1.4 N 1 1.2 z " 1 0 v 5 h 0.8 0 0.6
Page 196 and 197:
7.6. GIANT AND COLOSSAL MAGNETORESI
Page 198 and 199:
7.7. FERROFLUIDS 187 Figure 7.22. M
Page 200 and 201:
7.7. FECIROFLUIDS 189 Figure 7.25.
Page 202 and 203:
7.7. FERRQFLUlOS 191 FerroRuids can
Page 204 and 205:
FURTHER READING FURTHER READING 193
Page 206 and 207:
10- IR f IA -1 8.1. INTRODUCTION 19
Page 208 and 209:
8.2. INFRARED FREQUENCY RANGE 197 1
Page 210 and 211:
8.2. INFRARED FREQUENCY RANGE 199 d
Page 212 and 213:
s C CTI e 8 9 4( 8.2. INFRARED FREQ
Page 214 and 215:
8.2.3. Raman Spectroscopy 8.2. INFR
Page 216 and 217:
8.2. INFRARED FREQUENCY RANGE 205 a
Page 218 and 219:
- r I 520 51 8 v 6 516 a" 51 4 51 2
Page 220 and 221:
8.2. INFRARED FREQUENCY RANGE 209 i
Page 222 and 223:
v) - C 3 8 600 400 100 0 e e 10 20
Page 224 and 225:
i E (cm-’ ) 20 c I 1 ID 0 4x107 8
Page 226 and 227:
- ? m v .- - z In C a, c C - .. . .
Page 228 and 229:
Excitatior I [eV]: 2.175 2.214 2.25
Page 230 and 231:
6 100 200 300 Time (ns) 8.3. LUMINE
Page 232 and 233:
400 nm Laser / Free excitons Trappe
Page 234 and 235:
8.4. NANOSTRUCTURES IN ZEOLITE CAGE
Page 236 and 237:
FURTHER READING 225 P. Milani and C
Page 238 and 239:
9.2. PREPARATION OF QUANTUM NANOSTR
Page 240 and 241:
i 9.2. PREPARATION OF QUANTUM NANOS
Page 242 and 243:
9.3. SIZE AND DIMENSIONALITY EFFECT
Page 244 and 245:
Page 246 and 247:
Page 248 and 249:
w n 3 2 1 9.3. SIZE AND DIMENSIONAL
Page 250 and 251:
Page 252 and 253:
Page 254 and 255:
WE) Quantum Dot Number of Electrons
Page 256 and 257:
9.5. SINGLE-ELECTRON TUNNELING 245
Page 258 and 259:
9.5. SINGLE-ELECTRON TUNNELING 247
Page 260 and 261:
1 pair section ;- COT. .; . . I. .
Page 262 and 263:
o.6 LWIR: T = 77 K 45" incidence AD
Page 264 and 265:
9.7. SUPERCONDUCTIVITY 253 horizont
Page 266 and 267:
9.7. SUPERCONDUCTIVITY 255 applied
Page 268 and 269:
10.1. SELF-ASSEMBLY 10 SELF-ASSEMBL
Page 270 and 271:
10.1. SELF-ASSEMBLY 259 factor of 2
Page 272 and 273:
(a) (LI (dl 10.1. SELF-ASSEMBLY 261
Page 274 and 275:
10.1. SELF-ASSEMBLY 263 atoms, as n
Page 276 and 277:
- c v) ._ C 3 2 9 40 c - .- e m v w
Page 278 and 279:
10.2. CATALYSIS 267 where the lengt
Page 280 and 281:
10.2. CATALYSIS 269 are also other
Page 282 and 283:
1600 2 1200 t p - Bi2M020, 10.2. CA
Page 284 and 285:
7 - I 2,330 m .- c r 0 2 2,300 - u)
Page 286 and 287:
10.2. CATALYSIS 275 with a top and
Page 288 and 289:
10.2. CATALYSIS 277 based on the pr
Page 290 and 291:
10.2. CATALYSIS 279 CnHlnfl, which
Page 292 and 293:
I1 ORGANIC COMPOUNDS AND POLYMERS 1
Page 294 and 295:
11.2. FORMING AND CHARACTERIZING PO
Page 296 and 297:
1 1.3. NANOCRYSTALS 285 This expres
Page 298 and 299:
-1 5 0) C a, -1 1 000 300 100 30 10
Page 300 and 301:
11.3. NANOCRYSTALS 289 Table 11.1.
Page 302 and 303:
11.3. NANOCRYSTALS 291 R’ groups
Page 304 and 305:
11.4. POLYMERS 293 Figure 11.9. Ske
Page 306 and 307:
11.5. SUPRAMOLECULAR STRUCTURES 295
Page 308 and 309:
M Et3P OTf M=Pd M=Pt M=Pd, 41 % M=P
Page 310 and 311:
11.5. SVPRAMOLECUUAR STRUCTURES 2s
Page 312 and 313:
Page 314 and 315:
11 5. SUPRAMOLECULAR STRUCTURES 303
Page 316 and 317:
Page 318 and 319:
BiodegradaWe surface 4 Functional g
Page 320 and 321:
FURTHER READING 309 F. J. Owens and
Page 322 and 323:
12.2. BIOLOGICAL BUILDING BLOCKS 31
Page 325 and 326:
314 BIOLOGICAL MATERIALS which we w
Page 327 and 328:
316 BIOLOGICAL MATERIALS Table 12.2
Page 329 and 330:
318 BIOLOGICAL MATERtALS i J / Flgu
Page 331 and 332:
320 BIOLOGICAL MATERIALS Pyrimidine
Page 333 and 334:
322 BlOLMjlCAL MATERiALS (a) DNA do
Page 335 and 336:
324 BIOLOGICAL MATERIALS so each wo
Page 337 and 338:
326 BIOLOGICAL MATERIALS 12.4.2. Mi
Page 339 and 340:
328 BIOLOGICAL MATERIALS tions they
Page 341 and 342:
330 BIOLOGICAL MATERIALS hardened f
Page 343 and 344:
13 NANOMACHINES AND NANODEVICES In
Page 345 and 346:
334 NANOMACHINES AND NANODEVICES CA
Page 347 and 348:
336 NANOMACHINES AND NANODEVICES Op
Page 349 and 350:
338 NANOMACHINES AND NANODEVICES ti
Page 351 and 352:
340 NANOMACHINES AN0 NANODEVICES PO
Page 353 and 354:
342 NANOMACHINES AND NANODEVICES X
Page 355 and 356:
344 NANOMACHINES AND NANODEVICES na
Page 357 and 358:
346 NANOMACHINES AND NANODEVICES 31
Page 359 and 360:
348 NANOMACHINES AND NANODEVICES -
Page 361 and 362:
350 NANOMACHINES AND NANODEVICES re
Page 363 and 364:
352 NANOMACHINES AND NANODEVICES 1
Page 365 and 366:
354 NANOMACHINES AND NANODEVICES -1
Page 368 and 369:
A.l. INTRODUCTION APPENDIX A FORMUL
Page 370 and 371:
A.3. PARTIAL CONFINEMENT 359 limiti
Page 372 and 373:
APPENDIX B TABULATIONS OF SEMICONDU
Page 374 and 375:
TABULATIONS OF SEMICONDUCTING MATER
Page 376 and 377:
Table B.8. Effective masses m+ rela
Page 378 and 379:
Page 380:
Page 383 and 384:
372 INDEX amoeba, 3 16 amphiphilic,
Page 385 and 386:
374 INDEX CdS, 9, 130, 213, 216, 36
Page 387 and 388:
376 INDEX dispersion, 277 disulfide
Page 389 and 390:
378 INDEX Ga (gallium) (continued)
Page 391 and 392:
380 INDEX length (continued) critic
Page 393 and 394:
382 INDEX multiple ionization, 93 r
Page 395 and 396:
384 INDEX pi-conjugation, 282, 292
Page 397 and 398:
silica, 269 silica-alumina, 269, 27
Page 399:
388 INDEX wavefimction (continued)
show all

Introduction to Nanotechnology

Create successful ePaper yourself

Delete template?

Save as template?