DC conductivity and charge transport in vitreous As2S3Ge8 – Te films

Abstract

Amorphous tellurium and Te based quaternary films have been grown onto both glassy (Pyrex) and ceramic Al2O3 substrates by a high speed thermal deposition in vacuum. The SEM and XRD analysis of the films was provided and the DC conductivity was studied in order to elucidate the influence of Te concentration on mechanisms of charge transport. It was shown that both material composition and substrate influence the phase-state structure of the films, which results in a strong variation of their parameters and electrical properties. The electrical conductivity is shown to be realized by either charge transport via extended states or hopping via localized states in valence band tail, dependently on the film composition and temperature regime.