Composition and Optical Dispersion Characterization of Nanoparticles ZnO-NiO Thin Films: Effect of Annealing Temperature

Thin films of ZnO0.7NiO0.3 have deposited on glass substrates at room temperature by using thermal evaporation technique under vacuum 10-5 mbar. The optical properties and dispersion parameters of the films have been studied. Changes in direct optical energy band gap of films were confirmed before and after annealing. The optical energy gap Eg decreased from 3.11 to 2.86 eV with increasing of annealing temperature to 200 ºC. Some of the optical absorption parameters, such as optical dispersion energies Eo and Ed, Urbach tails EU , dielectric constant ε, the average values of oscillator strength So, and wavelength of single oscillator λo have been reported. An increase in the annealing temperature causes an increase in the average oscillator strength from 62.02 to 87.71 eV.