Investigation of structural, optical and electrical properties of ZnS thin films prepared by ultrasonic spray technique for photovoltaic applications

Abstract

ZnS films have important applications in photovoltaic devices. In the current study, the ZnS films were deposited by ultrasonic spray method on heated glass substrate at temperature equal to 450°C.In this article, we report the effect of deposition time on the different structural, optical and electrical properties of ZnS. All the samples obtained were treated using X-ray diffraction (XRD), optical transmittance spectroscopy (UV-V) and four-point method. The results of X-rays diffraction showed that the deposited material was pure zinc sulfide having a cubic sphalerite structure with preferential orientation along the (111) direction. As well the grain size was around 38–102nm, when the deposition time increases. The transmittance measurements exhibit an average optical transparency between 35 and 75% in the visible range (400–750nm) for different deposition times. The direct band gap energy for all films was calculated and found to be from 3.48 to 3.92eV. The films' thickness is increased with deposition time from 195nm to 1756nm. The electric resistivity of the deposited film varies also with the deposition time between 1.51×105 and 20.84×105Ω.cm.