Effect of annealing on the optical properties of thermally evaporated ZnO films

Two zinc oxide samples with different film thicknesses have been thermally evaporated on unheated glass substrate using ZnO high-purity powder. The fi lms were subjected to post-deposition annealing in air at different tempera tures. X-ray diffraction confirmed that the films in the as-deposited as we ll as after annealing are in the amorphous state. The optical properties we re studied by transmittance and reflectance measurements. The integrated vi sible (T-vis), and solar, T-sol, transmittance were calculated. The depende nce of absorption coefficient and the refractive index on wavelength before and after post-deposition heat treating was also reported, (C) 2001 Elsevi er Science Ltd. All rights reserved.