Phonons in Nanostructures

by Michael A. Stroscio

Overview

Stroscio (physics, Duke U.) and Dutta (the Army Research Office's Director of Research and Technology Integration) focus on the study of phonons and phonon-mediated effects in structures with nanoscale dimensional confinement in one or more spatial dimensions. Pertinent to the field of optoelectronics, quantum electronics, materials science, chemistry, and biology, the phenomenon explored is important in technologies needed to fabricate nanoscale structures and devices. Geared toward practicing physicists, the theme of the work is the description of optical and acoustic phonons in such nanostructures as the superconductor superlattice, quantum wires, and carbon nanotubes.

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Product Details

ISBN-13:	2900521018059
Publication date:	08/22/2005
Pages:	292
Product dimensions:	6.00(w) x 1.25(h) x 9.00(d)

About the Author

Dr. Michael A. Stroscio earned a Ph.D. in Physics from Yale University and held research positions at the Los Alamos Scientific Laboratory and the Johns Hopkins University Applied Physics Laboratory, before moving into the management of federal research and development at a variety of U.S. government agencies. Dr. Stroscio has served as a policy analyst for the White House Office of Science and Technology Policy, and as Vice Chairman of the White House Panel on Scientific Communication. He has taught and lectured on Physics and Electrical Engineering at several universities including Duke University, the North Carolina State University and the University of California at Los Angeles.

Table of Contents

	Preface	xi
Chapter 1	Phonons in nanostructures	1
1.1	Phonon effects: fundamental limits on carrier mobilities and dynamical processes	1
1.2	Tailoring phonon interactions in devices with nanostructure components	3
Chapter 2	Phonons in bulk cubic crystals	6
2.1	Cubic structure	6
2.2	Ionic bonding - polar semiconductors	6
2.3	Linear-chain model and macroscopic models	7
2.3.1	Dispersion relations for high-frequency and low-frequency modes	8
2.3.2	Displacement patterns for phonons	10
2.3.3	Polaritons	11
2.3.4	Macroscopic theory of polar modes in cubic crystals	14
Chapter 3	Phonons in bulk wurtzite crystals	16
3.1	Basic properties of phonons in wurtzite structure	16
3.2	Loudon model of uniaxial crystals	18
3.3	Application of Loudon model to III-V nitrides	23
Chapter 4	Raman properties of bulk phonons	26
4.1	Measurements of dispersion relations for bulk samples	26
4.2	Raman scattering for bulk zincblende and wurtzite structures	26
4.2.1	Zincblende structures	28
4.2.2	Wurtzite structures	29
4.3	Lifetimes in zincblende and wurtzite crystals	30
4.4	Ternary alloys	32
4.5	Coupled plasmon-phonon modes	33
Chapter 5	Occupation number representation	35
5.1	Phonon mode amplitudes and occupation numbers	35
5.2	Polar-optical phonons: Frohlich interaction	40
5.3	Acoustic phonons and deformation-potential interaction	43
5.4	Piezoelectric interaction	43
Chapter 6	Anharmonic coupling of phonons	45
6.1	Non-parabolic terms in the crystal potential for ionically bonded atoms	45
6.2	Klemens' channel for the decay process LO [right arrow] LA(1) + LA(2)	46
6.3	LO phonon lifetime in bulk cubic materials	47
6.4	Phonon lifetime effects in carrier relaxation	48
6.5	Anharmonic effects in wurtzite structures: the Ridley channel	50
Chapter 7	Continuum models for phonons	52
7.1	Dielectric continuum model of phonons	52
7.2	Elastic continuum model of phonons	56
7.3	Optical modes in dimensionally confined structures	60
7.3.1	Dielectric continuum model for slab modes: normalization of interface modes	61
7.3.2	Electron-phonon interaction for slab modes	66
7.3.3	Slab modes in confined wurtzite structures	71
7.3.4	Transfer matrix model for multi-heterointerface structures	79
7.4	Comparison of continuum and microscopic models for phonons	90
7.5	Comparison of dielectric continuum model predictions with Raman measurements	93
7.6	Continuum model for acoustic modes in dimensionally confined structures	97
7.6.1	Acoustic phonons in a free-standing and unconstrained layer	97
7.6.2	Acoustic phonons in double-interface heterostructures	100
7.6.3	Acoustic phonons in rectangular quantum wires	105
7.6.4	Acoustic phonons in cylindrical structures	111
7.6.5	Acoustic phonons in quantum dots	124
Chapter 8	Carrier-LO-phonon scattering	131
8.1	Frohlich potential for LO phonons in bulk zincblende and wurtzite structures	131
8.1.1	Scattering rates in bulk zincblende semiconductors	131
8.1.2	Scattering rates in bulk wurtzite semiconductors	136
8.2	Frohlich potential in quantum wells	140
8.2.1	Scattering rates in zincblende quantum-well structures	141
8.2.2	Scattering rates in wurtzite quantum wells	146
8.3	Scattering of carriers by LO phonons in quantum wires	146
8.3.1	Scattering rate for bulk LO phonon modes in quantum wires	146
8.3.2	Scattering rate for confined LO phonon modes in quantum wires	150
8.3.3	Scattering rate for interface-LO phonon modes	154
8.3.4	Collective effects and non-equilibrium phonons in polar quantum wires	162
8.3.5	Reduction of interface-phonon scattering rates in metal-semiconductor structures	165
8.4	Scattering of carriers and LO phonons in quantum dots	167
Chapter 9	Carrier-acoustic-phonon scattering	172
9.1	Carrier-acoustic-phonon scattering in bulk zincblende structures	172
9.1.1	Deformation-potential scattering in bulk zincblende structures	172
9.1.2	Piezoelectric scattering in bulk semiconductor structures	173
9.2	Carrier-acoustic-phonon scattering in two-dimensional structures	174
9.3	Carrier-acoustic-phonon scattering in quantum wires	175
9.3.1	Cylindrical wires	175
9.3.2	Rectangular wires	181
Chapter 10	Recent developments	186
10.1	Phonon effects in intersubband lasers	186
10.2	Effect of confined phonons on gain of intersubband lasers	195
10.3	Phonon contribution to valley current in double-barrier structures	202
10.4	Phonon-enhanced population inversion in asymmetric double-barrier quantum-well lasers	205
10.5	Confined-phonon effects in thin film superconductors	208
10.6	Generation of acoustic phonons in quantum-well structures	212
Chapter 11	Concluding considerations	218
11.1	Pervasive role of phonons in modern solid-state devices	218
11.2	Future trends: phonon effects in nanostructures and phonon engineering	219
	Appendices	221
Appendix A	Huang-Born theory	221
Appendix B	Wendler's theory	222
Appendix C	Optical phonon modes in double-heterointerface structures	225
Appendix D	Optical phonon modes in single- and double-heterointerface wurtzite structures	236
Appendix E	Fermi golden rule	250
Appendix F	Screening effects in a two-dimensional electron gas	252
	References	257
	Index	271