Phonon strain-shift coefficients ofSi1−xGe

Measurement of phonon pressure coefficients for a precise determination of deformation potentials in SiGe alloys

“…A striking result concerns the fact that the Grüneisen parameters of all three modes are almost constant and very similar in absolute value, being its average equal to 1.00 ± 0.05. This is in clear contrast with several literature sources, where γ values as large as 1.3 to 1.4 are reported for intermediate Ge concentrations [4,6]. Furthermore, a constant γ implies that the observed variation of the phonon pressure coefficient with alloy composition (see Fig.…”

“…The expression for the strain shift coefficient as a function of the DPs is given by [2,6] s 0 11 12…”

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

“…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 .…”

Raman characterization of strain and composition in small-sized self-assembled Si/Ge dots

“…For the Si-Si mode, b Si-Si ϭ-1050 cm Ϫ1 when x Ge ϭ0.8. 21 Thus, an average strain of Ϫ3.4% is obtained for the Ge-rich regions in Si/Ge dots from the frequency shift of the Si-Si mode.…”