The features of the intrinsic photoconductivity spectra of silver-doped zinc sulphide Scientific paper

Abstract

The intrinsic photoconductivity of silver-doped zinc sulphide (ZnS:Ag) was investigated. It was shown that doping with silver leads to significant modifications in the electronic structure and optical properties of ZnS due to the formation of localized energy levels within the band gap. Mechanical polishing of the sample surface resulted in the appearance of an additional photocon­duct­ivity maximum near the fundamental absorption edge, which gradually disap­pears during sample ageing. These effects are attributed to the compensation of donor and acceptor states, as well as to changes in charge carrier recombination mechanisms. The dependence of the photoconductivity spectrum on ageing time, the applied electric field, and the position of illumination relative to the contacts was established. The results are explained by variations in the lifetime of non-equilibrium charge carriers with depth. A qualitative model describing the photo­conductivity spectra is proposed, taking into account the influence of silver com­pensation on the energy structure of ZnS. The proposed model provides insight into the photoconductive mechanisms and supports the development of ZnS-
-based optoelectronic materials.