Raman coupling-parameter variation in amorphous silicon

The Raman coupling-parameter variation of an a-Si film has been obtained from depolarized--Raman-scattering measurements by using inelastic--neutron-scattering results. The frequency variation is found to be quite similar to that of a-Ge with appropriate frequency scaling. The coupling parameter is utilized to calculate from the Raman spectra the approximate density of states of a maximally ordered, chemical-vapor-deposited a-Si film. The resulting density of states is shown to be in good agreement with the theoretical density of states of a Beeman model which is estimated to have a similar bond-angle deviation.