Synthesis and Characterization of ZnS Nanopowders and Thin Films

In this article, nanopowder zinc sulfide (ZnS) was chemically precipitated starting from Zn powder and diluted HCl to make a ZnCl2 solution followed by a reduction process using a laboratory-prepared Na2S. Na2S was produced by dissolving NaOH in distilled water. Then, according to the stochiometric values of the compound, high-purity S powder was added while heating and stirring the mixture to a temperature of approximately 105 oC. The mixture was finally dried under a vacuum at 200 oC. The produced ZnS was studied using SEM coupled with EDS, XRD analysis, UV-Vis, and FTIR techniques. The results confirmed the synthesis of nanoscale ZnS powder and its chemical composition. To prepare ZnS pellets, the ZnS nanopowder was compacted and sintered under an Argon atmosphere at 400°C for 8 hours. The SEM and EDS examined the microscopic structure of the sintered pellets. The sintered ZnS pellets were also used as an evaporation source for thin deposition via E-beam evaporation. Furthermore, the optical properties of the deposited thin films were studied using UV-Visible spectroscopy in the wavelength range of 190 -1100 nm, where the energy gaps (Eg) were calculated for thin films with thicknesses of 111 nm and 40 nm, and they were around 4.72 eV and 5.82 eV, respectively. This article offers a facile production route of a high-purity ZnS nanopowder and its application as an evaporation source for the E-beam deposition of ZnS thin films.