In this study, preparation of Sn and Si co doped (0–3 mol % Sn and Si) ZnO dip-coated thin films on glass substrate via sol–gel process have been investigated. The effects of Sn and Si content on the structural and optical properties of applied thin films have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Uv-vis spectroscopy. XRD patterns showed a decrease in peak intensities of Zinc Oxide crystalline phase which is result of increasing the Sn and Si co-dopant. The optical band gaps of the films were calculated. This suggests that the absorption edge shifts to the higher wavelengths with Sn and Si dopant. The optical absorption spectrum indicates that the ZnO thin films have a direct band gap of 3.41eV. But optical band gap of the doped ZnO was found to be 2.64-3.35eV.
