An investigation on structural and optical properties of Zn1-xMgxS thin films deposited by RF magnetron co-sputtering technique

Abstract

In this paper, Zn1-xMgxS thin films were co-sputtered on glass substrates using ZnS and MgS binary target materials under various applied RF power. The compositional ratio of Zn1-xMgxS films was varied by changing the RF power at an elevated temperature of 200 °C. The structural and optical properties were studied in detail. The structural analysis shows that the co-sputtered Zn1-xMgxS thin films have a cubic phase with preferred orientation along the (111) plane. The lattice constant and ionicity suggest the presence of a zincblende structure in Zn1-xMgxS thin films. Zn1-xMgxS thin films have transmittance over 76%. The extrapolation of optical characteristics indicates that direct bandgaps, ranging from 4.39 to 3.25 eV, have been achieved for the grown Zn1-xMgxS films, which are desirable for buffer or window layers of thin film photovoltaics.