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 Zn<inf>x</inf>Sn<inf>1-x</inf>S thin film, one can expect exceptional opto-electrical properties due to their large band gap dissimilarity. Herein, thin films of Zn<inf>x</inf>Sn<inf>1-x</inf>S (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 Zn<inf>x</inf>Sn<inf>1-x</inf>S 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 2? 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 Zn<inf>x</inf>Sn<inf>1-x</inf>S 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 Zn<inf>x</inf>Sn<inf>1-x</inf>S films was varied. The various opto-electrical parameters were investigated and the photosensitivity was found highest at 43.38 for the Zn<inf>0.10</inf>Sn<inf>0.90</inf>S films. The observed tunable opto-electrical properties of the Zn<inf>x</inf>Sn<inf>1-x</inf>S films suggests that the films can be utilized for a wide range of opto-electronic applications. © 2020 International Solar Energy Society