High-field conduction in semi-insulating ZnS films

Abstract

Recent experimental findings on high-field conduction in polycrystalline and epitaxial semi-insulating ZnS films embedded in metal–insulator–metal structures are interpreted in terms of a bulk-controlled mechanism involving the deep centres responsible for self-compensation of the material. Conduction features showing marginal temperature dependence involve electron exchange between the deep donors and the conduction band. Temperature-dependent conduction features involve hole generation and interaction with deep acceptors. The qualitative agreement of the model with experimental evidence does not rely on a specific choice of the deep-centre parameters. Application of the framework to the commercial ZnS-based electroluminescence structures is discussed. The framework is of interest to high-field conduction in undoped wide-gap materials.