Structural and optical properties of ZnO thin films prepared by spray pyrolysis for different substrate temperatures

ZnO thin films can be grown by various techniques implemented by various temperatures. We present the Morphological and Optical properties of ZnO thin films prepared by using spray pyrolysis on glass substrates at various growth temperatures from 150oC, 200oC, 250oC. The surface morphology of the films analysed by scanning electron microscopy SEM. The optical energy gap for all thin films was calculated using Tauc’s equation. The band gap of ZnO films increases with increasing substrate temperatures attributed to the increase of the grain size of the sample. The calculated band gap energy of ZnO thin films deposited at 150oC, 200oC, 250oC varies from 3.2eV to 3.32eV, which correspond to a slightly change in the band gap energy with the substrate temperature. From X-ray diffractometry measurements, zinc oxide thin films showed hexagonal wurtzite structure.