In the present work, ZnS thin film was deposited onto a p-type Si-substrate using the chemical bath deposition method, and subsequently Ag/n-ZnS/p-Si/Ag heterojunction device was fabricated to investigate its diode parameters in the temperature range of 0–60 °C. Cubic zinc blende phase of the prepared ZnS thin film was confirmed using grazing incidence X-ray diffraction (GIXRD); Scherrer analysis revealed a lower limit of crystallite size as 2.4 nm. Scanning electron microscopy (SEM) revealed the surface morphology of the prepared ZnS thin film, which exhibited good homogeneity and density. UV–Visible absorption spectroscopy revealed the good UV-region absorbance and visible-region transmittance of the deposited ZnS thin film. The corresponding energy band gap was obtained from Tauc analysis and found to be 3.88eV. Photoluminescent emission (PLE) spectroscopy showed the defect mediated radiative transitions in the deposited ZnS thin film. Current-voltage (I–V) measurements of the fabricated heterojunction device exhibited Schottky diode behaviour. Diode parameters of reverse saturation current, Schottky barrier height, ideality factor and series resistance were obtained from the I–V measurements in the temperature range of 0–60 °C; barrier height was obtained in the range of 0.87–0.74eV, and ideality factor was obtained close to unity for I–V measurements made at 30 °C and 60 °C.