Local structure and electronic properties of amorphous As2S3 films prepared by different methods

Abstract

The local structure of amorphous As2S3 films prepared by thermal evaporation in vacuum and by RF ion-plasma sputtering has been analysed by Raman spectroscopy. Also, the carrier drift in the films and their electrical and optical properties have been studied. Differences in dark conductivity, activation energy of conductivity, optical gap, shift of the Fermi level with respect to midgap and essential differences in their local atomic structure and electron drift mobility have been established. A conclusion is made that these differences are due to the fact that the matrix of the films obtained by ion sputtering contains, in addition to the structural units common to those in films prepared by vacuum evaporation, units of another type, with a predominance of As–As bonds.