Phonons in semiconductor nanostructures springerlink. The heat transfer from graphene nanostructure to its surrounding may have unique characteristics which should be taken into account in the models employed for the thermal transport study. Damping pathways of midinfrared plasmons in graphene nanostructures hugen yan1,tonylow1, wenjuan zhu1,yanqingwu1,marcusfreitag1,xuesongli1, francisco guinea2, phaedon avouris1 and fengnian xia1 plasmon is the quantum of the collective oscillation of electrons. Phonons in nanostructures request pdf researchgate. Click download or read online button to optical properties of semiconductor nanostructures book pdf for free now.
Models for confined phonons in semiconductor nanostructures, latest experimental observations of confined phonons and electronphonon interaction in twodimensional systems, elementary excitations in nanostructures, phonons and optical processes in reduced dimensionality systems, phonon limited transport phenomena, hot electron effects in quasi id structures, carrier relaxation and phonon bottleneck in quantum dots. Monte carlo modeling of phonon transport in nanostructures. The strong lateral size dependence of tr motivates us to formally check if. Spatial confinement of electrons and phonons in nanostructures strongly affects their energy spectra, density of states and electronphonon interaction. We determine for several iiiv and iivi semiconductor multilayer nanostructures the frequencies for the first excited if modes. Phonon coherence and its effect on thermal conductivity of. Damping pathways of midinfrared plasmons in graphene. Phonon transistors in nanostructures anvar zakhidov on behalf of utd peom team dsrc nanoscopic phonon engineering workshop booz allen hamilton, arlington, may 9, 2005 2 anvar a. Cleland1, 1department of physics, university of california, santa barbara, california 93106, usa 2department of applied physics and physics, yale university, new haven, connecticut 06520, usa received 28 august 2003. For exciting phonons in nanostructures is necessary some, different from zero, activation energy. Optical properties of semiconductor nanostructures. Phonon assisted optical properties of semiconductor. The properties of confined, interface and propagating modes in wurtzite quantumconfined structures may be described theoretically in terms of the dielectric continuum and loudons model for uniaxial semiconductors.
Designing nanostructures for interfacial phonon transport. Nikaa,b adepartment of electrical engineering and materials science and engineering program, bourns college of engineering, university of california, riverside, ca. Request pdf phonons in nanostructures this book focuses on the theory of phonon interactions in nanoscale structures with particular emphasis on modern. Stroscio, mitra dutta this book focuses on the theory of phonon interactions in nanoscale structures with particular emphasis on. Spatial confinement of electrons and phonons in nanostructures strongly affects their energy spectra, density of states and electronphonon. A key goal is to describe tractable models of confined phonons and how these are applied to calculations of basic properties and phenomena of semiconductor heterostructures. A detailed study on phonon transport in thin silicon.
The atomic position were given as function of the primitive lattice vectors v 1 1 2. Nanostructures open exciting opportunities for tuning the phonon energy spectrum and related properties of materials for specific applications. Title speaker video lecture link text document link views 1 profintroduction to nanomaterialsc1. However, it was predicted that the thermal conductivity of nanostructures embedded within the acoustically hard barrier layers can be increased via spatial confinement of acoustic phonons 6, 9, 26. The level of presentation is appropriate for undergraduate and graduate students in physics and engineering with some background in quantum mechanics and solid state physics or devices. Motivation for tuning phonon kt in our 2 main systems. Heat guiding and focusing using ballistic phonon transport. Phonons in nanostructures there are no such things as applied sciences, only applications of sciences. A common method to improve thermoelectric performance is to reduce thermal conductivity by enhancing phonon scattering.
For quantum wells these properties include electron relaxation, infrared absorption, temperature dependent exciton linewidths, and phonon assisted exciton absorption and emission. The coherent transport of phonons allows for the control of thermal conductivities in nanostructures with a secondary periodicity such as sls and nms by modifying the phonon dispersion relations, thus changing the group velocities and the density of states dos of phonons. The if or surface optical so phonons are associated to the crystal boundary surfaces and they are due to different dielectric constants at the interfaces. Coupled electronphonon transport and heat transfer. Proceedings of the nato advanced research workshop on phonons in semiconductor nanostructures, st. The possibilities for controlled modification of the phonon transport and phonon interactions referred to as phonon. Roukes1 1condensed matter physics, california institute of technology, mail code 11436, pasadena, california 91125 2laboratory for physical sciences, university of maryland, college park, maryland 20740 3department of physics, university of utah, salt lake city, utah 84112. In nanostructures phonons usually dominate and the phonon properties of the structure become of a particular importance for thermal conductivity. Engine ering phonons in nanostructures and graphene alexander a. Role of nanostructures in reducing thermal conductivity. While acoustic phonons are strongly scattered at boundaries and interfaces, optical phonons have short mean free paths mfps and are scattered much more strongly inside the nanostructures than at the boundaries. The critical role of phonons in semiconductor nanoscale devices is well known and a key goal of this book is to describe tractable models of confined phonons and how they are applied to calculations of basic properties and phenomena of semiconductor heterostructures. Models for confined phonons in semiconductor nanostructures, latest experimental observations of confined phonons and electronphonon interaction in twodimensional systems, elementary excitations in nanostructures, phonons and optical processes in reduced dimensionality systems, phonon limited transport phenomena, hot electron effects in quasi id structures, carrier relaxation and phonon. Electron and phonon transport in silicon nanostructures.
Particularly, this dissertation emphasizes advancing understanding of the meanfreepaths i. Examples are given to demonstrate the importance of nanoscale heat. This book focuses on the theory of phonon interactions in nanoscale structures with particular emphasis on. Electrons and phonons manifest themselves in all properties of materials. Conclusive experimental evidence of acoustic phonon confinement in individual freestanding nanostructures was missing. Download optical properties of semiconductor nanostructures ebook pdf or read online books in pdf, epub, and mobi format. Phonons in semiconductor nanostructures book, 1993. This dissertation presents experimental studies of heat transport by phonons in crystalline materials and nanostructures, and across solidsolid interfaces.
Ballistic phonon transport in silicon films phononboundary scattering has been investigated. Boltzmann transport equation for phonons phonons obey to the boltzmann transport equation bte. In the last ten years, the physics and technology of low dimensional structures has. Phonons and defects in semiconductors and nanostructures. The central theme of this book is the descrip tion of the optical and acoustic phonons, and their interactions, in nanostructures. In this paper, a frequencydependent phonon radiative transport equation prte solver, based on the discrete ordinates method, is developed to simulate phonon transport in thin silicon membranes with phononic crystal nanostructures. The continuum assumption fails in the nanoscale regime where either mean free path or wavelength of the phonons becomes comparable with the characteristic dimension of the nanostructures. Since the defects in alloys are atomic in size, they are most effective in scattering short wavelength phonons, i.
The results indicate that around room temperature, optical phonons can contribute over 20% to the thermal conductivity of nanostructures as compared to 5% in bulk materials. In such narrow gnrs, phonons propagating in or close to the length direction are the predominant heat carriers, and the upper and lower edges are the dominant phonon scattering centers. Phonon trapping, phonon scattering, and heat flow at heterojunctions s. Phonon scattering mechanisms in suspended nanostructures. Photonmediated thermal relaxation of electrons in nanostructures d. In addition, the temperature and size dependence of the contributions from acoustic and optical phonons are fully explored. Inelastic light scattering by phonons in hexagonal ganaln nanostructures. Bebek physics department, texas tech university, lubbock, texas 794091051, usa received 8 july 20. As opposed to electrons that contribute to conduction only near the fermi surface, phonons show broadband spectrum when they transport heat in silicon.
Crystalline semiconductor nanostructures have special properties associated with electrons and lattice vibrations and their interaction, and this is the topic of the. Hybrid acoustic and optical modes are described, with an emphasis on polaroptical phonons and their interaction with electrons. Pdf inelastic light scattering by phonons in hexagonal. The dominant heat carriers in graphene are phonons, and their interaction with electrons plays an important role in the heat dissipation in graphene based devices. Understanding electron and phonon transport in silicon nanostructures is essential for developing advanced electronic and thermoelectric systems. When considered as particles their motion and interactions scattering in nanostructures depends on. A key goal of this book is to describe tractable models of confined phonons and how these are applied to calculations of basic properties and phenomena of semiconductor heterostructures. In most of cases, the spatial confinement of acoustic phonons results in the reduction of the phonon thermal conductivity 2425. Such difference in scattering leads to a rebalance of the relative importance of optical phonons and acoustic phonons to the thermal conductivity of nanostructures. Phonon scattering mapping and temperature measurement in. Heat guiding and focusing using ballistic phonon transport in phononic nanostructures. Phonon scattering mechanisms in suspended nanostructures from 4 to 40 k w. Stroscio, mitra dutta this book focuses on the theory of phonon interactions in nanoscale structures with particular emphasis on modern electronic and optoelectronic devices. Stanton 1 1 department of physics, university of florida, gainesville, fl 2 department of physics, tohoku university, sendai 9808578, japan 3 center for integrated nanostructure physics cinap, institu te for basic science ibs.
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