Study of micro-structural properties of ZnO and TiO2 thin film grown by spray pyrolysis

Micro structural and optical properties of ZnO and TiO2 films prepared by spray pyrolysis were studied by XRD (X-ray diffraction) analysis and measurements of transmittance and Urbach Energy. The influence of preparation conditions on the micro structural properties of ZnO and TiO2 films was investigated throug the evaluation of the X-ray peak broadening. The Williamson Hall (W-H) analysis and size strain plot method were used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening. The physical parameters such as strain, stress and energy density values were calculated for all the reflection peaks of XRD corresponding to both type of samples from the modified form of the W-H plot assuming a uniform deformation model (UDM), uniform stress deformation model (USDM) and uniform deformation energy density model (UDEDM). It was found that the particle mean size of the ZnO and TiO2 films estimated from the W-H method agree quite good with AFM results. Further, information regarding the influence of preparation conditions on the formation of structural defects was achieved through Urbach energy measurements.