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

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 38-102 nm, when the deposition time increases. The transmittance measurements exhibit an average optical transparency between 35 and 75% in the visible range (400-750 nm) for different deposition times. The direct band gap energy for all films was calculated and found to be from 3.48 to 3.92 eV. The films' thickness is increased with deposition time from 195 nm to 1756 nm. The electric resistivity of the deposited film varies also with the deposition time between 1.51 × 105 and 20.84 × 105 Ω.cm.