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Showing 1 to 20 of 103 for “"Phonon scattering"”.
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Phonon Scattering From Monovalent Substitional Impurities in Sodium-Chloride
Made available in DSpace on 2015-05-12T21:41:38Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 6706575.PDF: 5658503 bytes, checksum: 1d93c1d7a8e68458317689bffdd8e75e (MD5) Previous issue date: 1966
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Phonon scattering from monovalent substitutional impurities in sodium chloride
This work was undertaken to investigate phonon scattering fl;'om monovalent substitutional impurities in sodium chloride using thefmal conductivity measurements as a tool. Similar work by other investi~ators on other alkali halides has shown that these defects scatter more strongly than the present …
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Phonon scattering by ferroelectric domain walls in potassium dihydrogen phosphate
I have studied phonon scattering by ferroelectric domain walls in KH2P04 (KDP) using thermal conductivity and phonon imaging measurements of samples in both single-domain (poled) and multidomain states. Domains were eliminated by applying a 2- 3kV /em field using evaporated electrodes. Phonon …
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Using high pressure to study thermal transport and phonon scattering mechanisms
… better understanding nanoscale heat transport by phonons across and away from material interfaces. The heat flux per unit temperature drop across an interface is quantified by the interface thermal conductance. This conductance is difficult to study, as it is comprised of at least three …
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Phonon Scattering From Substitutional Impurities and Lattice Defects in Silver-Chloride
Made available in DSpace on 2015-05-12T21:41:49Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 6910658.PDF: 3384587 bytes, checksum: dadaf091abb753ede9fb3bf70e7363a2 (MD5) Previous issue date: 1968
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Phonon Scattering From Substitutional Impurities and Lattice Defects in Cadmium-Sulfide
Made available in DSpace on 2015-05-12T21:41:50Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 6910799.PDF: 2471982 bytes, checksum: d9938384dcc01ec6e7c50c7698e0ae7c (MD5) Previous issue date: 1968
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Phonon scattering from substitutional impurities and lattice defects in cadmium sulfide
… gives a ""perfectly rough"" surface for boundary scattering of phonons. A theoretical analysis utilizing the Debye thermal conductivity integral was successfully applied to the data for the pure crystal. Coefficients derived from computer fits to the data agree with those calculated from …
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Phonon scattering from substitutional impurities and lattice defects in silver chloride
The purpose of this investigation was to study phonon scattering by substitutional impurities and lattice defects in silver chloride crystals by means of the thermal conductivity technique. In addition, far infrared absorption measurements were made on some of the doped crystals. The thermal …
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Investigating the Existence of Coherent Phonon Scattering in Silicon Using Phononic Crystals
… the majority of heat energy is transported by phonons, which are discrete lattice vibrations. Phonon scattering due to the presence of voids in silicon can further alter the materials thermal conductivity. There is a question about the possibility of some of this scattering being coherent …
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Acoustic Phonon Scattering in Modulation Doped Aluminum(x) Gallium(1-X) Arsenide/gallium Arsenide Heterojunctions
We investigate acoustic deformation potential scattering in Al$\sb{\rm x}$Ga$\sb{1-\rm x}$As/GaAs modulation doped heterojunctions. We review previous measurements of the deformation potential constant Z and discuss the controversy over the discrepancy between the measured value of Z in bulk GaAs …
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Computational Modeling of Geometry Dependent Phonon Transport in Silicon Nanostructures
… depend on nanostructure boundary geometry. Phonons are quantized mechanical vibrations that are the dominant carrier of heat in semiconductor materials and their aggregate behavior determine a nanostructure's thermal performance. Phonon-geometry scattering processes as well as waveguiding …
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Carrier relaxation in doped quantum wells
… encompasses both electron-electron and electron-phonon scattering taking into account the mutual interactions of the electrons and phonons. The intersubband relaxation time of an electron is numerically evaluated considering electron-electron and electron-phonon (bulk LO-phonon) scattering in a …
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Structural Characterization and Thermoelectric Performance of ZrNiSn Half-Heusler Compound Synthesized by Mechanical Alloying
… size achieved by MA and SPS causes increased phonon scattering due to the increased number of grain boundaries, which lowers the thermal conductivity without doping the base system with addition phonon scattering centers. Mechanical characterization of the samples by microindentation and depth …
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Electron-phonon interactions in double layer graphene superfluids
… condensate, it is important to consider the scattering of charge carriers by phonons in each of the constituent graphene monolayers. We use the non- equilibrium Green’s function (NEGF) formalism to examine the effect that carrier-phonon scattering has on transport in such a device. The …
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Effect of phonon transport on the Seebeck coefficient and thermal conductivity of silicon nanowire arrays
… that has been attributed to the increased scattering of heat conducting phonons from the surface disorder introduced by etching. The reduction is below the incoherent limit for phonon scattering at the boundary, the so-called Casimir limit. A new model of partially coherent phonon transport …
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The scattering of thermal phonons by extended defects in dielectric crystals
The scattering of thermal phonons by extended defects in dielectric crystals has been observed through measurements of thermal conductivity and ballistic heat pulse propagation. The thermal conductivities of LiF and NaCt containing 500 low-angle grain boundaries per cm were measured in the range …
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Analysis of the electron transport properties in quantum cascade lasers
… small subband separations in THz QCLs lead to LO-phonon scattering rates that are highly temperature sensitive and increases the importance of scattering processes which favor small transition energies, such as electron-electron (e-e), electron-impurity (e-imp)and electron-interface roughness …
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The scattering of high-frequency acoustic phonons in silicon and GaAs
… and propagation of high-frequency acoustic phonons in silicon and GaAs are studied at low temperatures (~ 2K) using the phonon imaging technique. In this technique, a heat source is provided by a focused laser beam which is raster scanned across the surface of the sample which is immersed in …
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Carrier momentum relaxation in highly doped polar semiconductors and semiconductor heterostructures
… of the carriers (plasmons) and the atoms (polar phonons) couple. These coupled collective excitations affect the electrical conductivity, here quantified through the carrier mobility. In scattering events, the carriers and the coupled collective modes transfer momentum between each other. Carrier …
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Electrical and thermal transport in 2- and 3-dimensional periodic holey silicon
… has been conclusively demonstrated that boundary scattering in nanostructured silicon e ectively reduces thermal transport, resulting in an enhanced thermoelectric Figure of merit ZT. However, claims of high ZT are quantitatively misleading since electrical and thermal properties are often …
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