The effect of solution flow rate and substrate temperature on structural and optical properties of TiO2 films deposited by spray pyrolysis technique

Titanium dioxide thin films have been deposited on glass substrate at various solution flow rates by spray pyrolysis technique with substrate temperatures between 350 °C-550 °C. Samples were characterized for structural, morphological and optical properties by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectrometry. The XRD analysis of deposited TiO2 films exhibited nanocrystalline nature and preferentially oriented along [101] direction. The UV-visible transmittance results show that all thin films were transparent with an average transmittance higher than 70% in the visible region. Due to nanosized grains, the optical band gaps of the TiO2 thin films (3.35-3.68 eV) were larger than the bulk TiO2 (3.2 eV). The SEM analysis revealed that thickness and morphology of TiO2 films can be adjusted by rate of solution flow and substrate temperature. It seems that the process of spray pyrolysis provides an easy way to prepare either homogeneous thin and thick films.