Production of Cu doped ZnS nanostructures and investigation of optical properties

In this study, copper sulphide (CuS), zinc sulphide (ZnS) and copper (Cu) doped zinc sulphide were produced. Cu doping ratios were adjust as 15%, 30%, 45%, 60%, 75%. In the production of thin films, sol-gel method was used which provides low cost and easy production. There are few studies in the literature about the production of Cu doped ZnS by sol–gel method. In this study, when the optical transmission of thin films produced at room temperature was compared and similar results were obtained with other production methods. Particularly, production at room temperature is different from that found in the literature. The coating of thin films on glass substrates was made via spin coating method, which is not previously used to coat Cu doped ZnS thin films nanostructures. Optical transmission and absorption analyzes of the coated thin films were made by UV-VIS Spectrophotometer. Band gaps were calculated with the help of Tauc formula using absorption measurements. The band gaps for CuS and ZnS nanostructures were calculated as 2.16 eV and 3.70 eV. Cu doping ratios were increased between 15% and 75% by 15% and band gaps were calculated as 3.50 eV, 3.21 eV, 3.02 eV, 2.96 eV and 2.82 eV, respectively. In the optical transmittance measurements, the transmittance of thin films were measured between 25% and 85%. Partical size of CuS, ZnS and Cu doped ZnS thin films nanotructures were investigated with Scanning Electron Microscopy (SEM). The size of nanoparticles was found to be between 13 and 30 nm. Energy Dispersive Spectroscopy (EDS) analysis of the same films was investigated. According to the results of the EDS, the doping percentages of the compounds were found. The crystal structures of CuS, ZnS and Cu doped ZnS nanostructures were investigated by X-Ray Diffraction (XRD) measurements.