The effect of oxygen atom substitution in the sulphur sites of the bulk ZnS: A DFT study

Abstract

Systematic first-principles calculations were performed, using the density functional theory (DFT) formalism to investigate the structural electronic and optical properties of ZnS1-xOx alloys in wurtzite phases. The electronic band structure shows that the fundamental band gap is direct at Γ point. The calculated band gap bowing disorder shows a largest contribution of the charge exchange. We demonstrate the formation of an isolated intermediate electronic band structure which may be attributed to coupling between impurity O-2p states in the conduction band. The optical parameters like dielectric function, optical reflectivity, absorption coefficient, transmittance spectra, and refractive index are performed. Moreover, the intermediate electronic level leads to active absorption of light and low transmittance below the band gap which can generate a significant photocurrent in ZnS1-xOx semiconductors.