Evidence for coupling of Si–Si lattice vibration and Si–D wagging vibration in deuterated amorphous silicon

The Raman spectra of hydrogenated and deuterated amorphous silicon films (a-Si:H, a-Si:D) have been investigated. It is suggested that the asymmetrical broadening of the transverse-optical (TO) Raman peak of a-Si:D compared to the TO Raman peak of a-Si:H results from the coupling between the Si–D wagging mode and the Si–Si TO phonon mode rather than the structural difference.