Raman Scattering by Local Modes in Germanium-Rich Silicon-Germanium Alloys

Feldman, D. W.; Ashkin, M.; Parker, James

doi:10.1103/physrevlett.17.1209

Cited by 136 publications

(26 citation statements)

References 15 publications

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“…19 We also observe additional Raman peaks near 400 cm -1 and 500 cm -1 in Ge-Si 0.5 Ge 0.5 core-shell nanowires, with an order of magnitude lower intensity, which we attribute to the Si x Ge 1-x shell's local Si-Ge and Si-Si modes, respectively. [20][21][22][23][24] Based on the relative intensity of the peak at ~300 cm -1 in comparison to the peaks located at 400 cm -1 and 500 cm -1 , we conclude the GeGe peak observed at ~300 cm -1 originates from the Ge core, a finding consistent with the relative volume ratio of the two regions. In both GeNWs and Ge-Si x Ge 1-x core-shell NWs, we have observed only a single peak at ~300 cm -1 .…”

Section: Methodssupporting

confidence: 69%

Raman spectroscopy and strain mapping in individualGe-SixGe1−xcore-shell nanowires

et al. 2012

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Section: Methodssupporting

confidence: 69%

Raman spectroscopy and strain mapping in individualGe-SixGe1−xcore-shell nanowires

et al. 2012

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“…Our experimental results will show that the harmonic mass disorder approximation under Matthiessen's rule is a sufficient approximation. We note that this procedure will not capture the frequency shifts that can be observed in the SiGe Raman spectra [21,22] (see the supplementary material). It is expected that these modes do not significantly contribute to thermal conductivity, as their group velocities are small and their lifetimes have been reduced by mass disorder scattering.…”

Section: Theory a First Principle Calculationsmentioning

confidence: 99%

Unifying first-principles theoretical predictions and experimental measurements of size effects in thermal transport in SiGe alloys

Huberman

Chiloyan

Duncan

et al. 2017

Phys. Rev. Materials

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In this work, we demonstrate the correspondence between first principle calculations and experimental measurements of size effects on thermal transport in SiGe alloys. Transient thermal grating (TTG) is used to measure the effective thermal conductivity. The virtual crystal approximation under the density functional theory (DFT) framework combined with impurity scattering is used to determine the phonon properties for the exact alloy composition of the measured samples. With these properties, classical size effects are calculated for the experimental geometry of reflection mode TTG using the recently-developed variational solution to the phonon Boltzmann transport equation (BTE), which is verified against established Monte Carlo simulations. We find agreement between theoretical predictions and experimental measurements in the reduction of thermal conductivity (as much as ∼ 25% of the bulk value) across grating periods spanning one order of magnitude. This work provides a framework for the tabletop study of size effects on thermal transport. * gchen2@mit.edu 1 arXiv:1704.01386v2 [cond-mat.mes-hall]

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“…I n contrast to the well developed studies in silicon and other materials, only limited experimental data on local modes in germanium are available a t present, Feldman et al [17] found the local modes of silicon in germanium by Raman scattering measurements. Cosand and Spitzer [ 181 observed recently by infrared absorption local modes in germanium due to lithium paired with gallium and also to aluminium impurities in unassociated and paired configurations.…”

Section: Introductionmentioning

confidence: 93%

Infrared Absorption by Local Vibrational Modes of Boron Impurities in Germanium

Nazarewicz¹,

Jurkowski²

1969

Physica Status Solidi (b)

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Local modes of boron in germanium have been observed b y infrared absorption measurements in the range from 480 to 630 cm-l a t 195 and 295 OK. Lithium has been used as a compensating donor impurity. The absorption spectrum contains three pairs of bands which are attributed t o local modes of boron on the basis of the isotopic shifts observed. One of these pairs is associated with unpaired (isolated) boron and two others with boron in paired configuration (with lithium), as was predicted theoretically. A comparison of our data with those already known for silicon is given.Les modes localises du bore dans le germanium ont kt6 observes par des mesures dabsorption infrarouge dans la region de 480 A 630 cm-' iL 195 et 295 "K. Le lithium a BtB utilise comme impureti. compensatrice. Le spectre d'absorption contient trois paires de bandes qui sont attribuees aux modes locaux du bore sur la base des dkplacements isotopiques observes. L'une de ces paires est attributee au bore isole et deux autres au bore associe au lithium, conformement aux previsions theoriques. Ces rbsultats sont compares B ceux d6jh connus dans le silicium.

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Raman Scattering by Local Modes in Germanium-Rich Silicon-Germanium Alloys

Cited by 136 publications

References 15 publications

Raman spectroscopy and strain mapping in individualGe-SixGe1−xcore-shell nanowires

Raman spectroscopy and strain mapping in individualGe-SixGe1−xcore-shell nanowires

Unifying first-principles theoretical predictions and experimental measurements of size effects in thermal transport in SiGe alloys

Infrared Absorption by Local Vibrational Modes of Boron Impurities in Germanium

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