Effect of nonstoichiometry on the electrical conductivity of erbium oxide films

Abstract

Thin films of erbium oxide show a thickness dependent amorphous‐to‐crystalline transformation. Both, the amorphous and crystalline phases are found to be nonstoichiometric with respect to oxygen content. electrical measurements of I‐U characteristics of these as‐grown films in a sandwich configuration, Al‐erbium oxide‐Al/Au, exhibit a voltage controlled negative resistance region (VCNR). The nature of the characteristic is independent of electrode material, electrode polarity, and vacuum conditions. It is postulated that the inherent nonstoichiometry of the film gives rise to a ‘built in’ localized energy band in the forbidden gap of the oxide films which is responsible for the occurrence of VCNR. Copyright © 1978 WILEY‐VCH Verlag GmbH & Co. KGaA