Raman Spectral Behavior of In1-xGaxP (0

We report on a Raman study of In1-xGaxP over the whole range of alloy compositions, x. The additional peak, which appeared for x\lesssim0.98 and about which various interpretations have been proposed, is found to be constructed by two unresolved modes. The Raman spectra indicate that this alloy system has a modified two-mode behavior. The spectral half width of a TO mode broadened in the middle of the alloy composition. This is partly due to the strong two-acoustic-phonons scattering process.