ZnS thin film has been grown on n-Si substrate for obtaining Zn/ZnS/n-Si/Au-Sb sandwich structure by using the Successive Ionic Layer Adsorption and Reaction (SILAR) method. For structural properties, the XRD and SEM measurements have been done and it is seen that films exhibit polycrystalline behavior. The energy band gap value of ZnS thin film grown glass substrate has been found as 3.77eV from the absorption measurements. The sandwich structure has demonstrated clearly rectifying behavior by the current–voltage (I–V) curves at room temperature Thermal annealing effect on the structural, optical and electrical properties has been investigated. From I–V characteristics n, Φ_b and mean R_s values have been calculated as 2.60, 0.71eV and 3.8kΩ at room temperature respectively. For annealed films at 400°C, these values have been found as 1.68, 0.62eV and 1.5kΩ, respectively. From C–V characteristics, carrier concentration, Fermi energy and barrier height values of this structure were calculated as a function of annealing temperature.