ZnxSn1-xS thin films: A study on its tunable opto-electrical properties for application towards a high efficient photodetector

Abstract

Zinc sulfide (ZnS) and tin sulfide (SnS) are crucial semiconductors with potential use in various opto-electronic applications. By incorporating ZnS and SnS to form ZnxSn1-xS thin film, one can expect exceptional opto-electrical properties due to their large band gap dissimilarity. Herein, thin films of ZnxSn1-xS (0.0 ≤ x ≤ 1.0) were successfully deposited on glass substrates using a thermal evaporation method for the first time and its various properties were analyzed. X-ray diffraction (XRD) analysis confirmed the polycrystalline behavior of ZnxSn1-xS films with a preferred orientation along the (1 1 1) plane. The absence of any secondary peaks along with the shift in the (1 1 1) peak position to lower 2θ values with increasing Zn concentration confirmed the formation of a solid solution. SEM analysis depicted the presence of uniform and homogeneous films. The formation of nearly stoichiometric ZnxSn1-xS films was verified using an energy dispersive spectroscopy (EDS). The electrical and optical properties of the films were estimated from the two-probe method and UV–Vis spectroscopy, respectively. The energy band gap values decreased from 3.49 eV to 1.54 eV as the composition of the ZnxSn1-xS films was varied. The various opto-electrical parameters were investigated and the photosensitivity was found highest at 43.38 for the Zn0.10Sn0.90S films. The observed tunable opto-electrical properties of the ZnxSn1-xS films suggests that the films can be utilized for a wide range of opto-electronic applications. © 2020 International Solar Energy Society