Photo-induced changes in glow-discharge-deposited amorphous silicon: The Staebler-Wronski effect

Abstract

The dramatic photo-induced changes in the electrical properties of glow-discharge-deposited amorphous silicon observed recently by Staebler and Wronski (1977) are discussed in the light of a model recently proposed by the author for defect states in this material. It is assumed that self-trapped excitons in the form of close pairs of oppositely charged defect centres are produced after irradiation with band-gap light. The Fermi level position is then moved nearer the mid-gap, accounting for the metastable decrease in d.c. conductivity, provided the samples are not heavily doped.