Raman characterization of twinning in heteroepitaxial semiconductor layers: GaAs/(Ca,Sr)F2

Abstract

Detailed analysis of Raman spectra recorded from (100)-oriented GaAs layers grown by molecular-beam epitaxy on the lattice-matched insulator (Ca,Sr)F2 gives evidence of internal misorientation effects (twins). This analysis accounts for the various phenomena (doping, disorder, electron-phonon coupling) likely to modify the scattering efficiency. Calculations are performed in order to obtain quantitative evaluations of the misoriented volume amount.