Phonon interactions in the tail states ofa-Si:H

Abstract

Many experimental data on the 1.4-eV photoluminescence of $a$-Si:H have been interpreted by the assumption of a Stokes shift of up to 0.5 eV. We show that the evidence for a Stokes shift may be satisfactorily explained by a distribution of zero-phonon energies only. This suggests that the radiative states may be rigid and so that there is no evidence for a significant disorder-induced electron-phonon interaction in the tail states of amorphous silicon.