Effects of Al Concentration on Structural and Optical Properties of Al-doped ZnO Thin Films

Aluminium (Al)-doped zinc oxide (AZO) thin films with different Al concentrations were prepared by the sol-gel spin-coating method. Optical parameters such as the optical band gap, absorption coefficient, refractive index, dispersion parameter, and optical conductivity were studied in order to investigate the effects of the Al concentration on the optical properties of AZO thin films. The dispersion energy, single-oscillator energy, average oscillator wavelength, average oscillator strength, and refractive index at infinite wavelength of the AZO thin films were found to be affected by Al incorporation. The optical conductivity of the AZO thin films also increases with increasing photon energy.