Compositional dependence of Raman frequencies in SixGe1−x alloys

Abstract

Increases in Si content and the calculated Raman spectra acquired from the SixGe1−x alloys reveal that the frequencies of the Ge—Si and Si—Si modes are up-shifted obviously, meanwhile that of the Ge—Ge optical mode is down-shifted, which is strongly dependent on their microstructural changes. The linear decrease and increase caused by their force constant (bond lengths and bond angles) changes, which can be used as a fingerprint to identify the average Si content. The complex microstructural changes induced by increasing Si content can be clearly displayed by Raman spectra transformation.