Effect of Al concentration on structural and optical property ZnO thin films as antireflecting coating

Al doped ZnO (AlxZn1–xO) thin films have been prepared on quartz substrates by the sol–gel method using zinc acetate dehydrate, aluminium nitrate, stabilised by diethanolamine with different concentrations of dopant (x=0, 0·05, 0·10 and 0·15 wt-%). Al doped ZnO thin films were annealed at 400°C for 2 h in air. The structural property of the films has been evaluated using X-ray diffraction, which showed that the spectra are crystalline structure with the single phase ZnO hexagonal wurtzite. The SEM images show that the surface morphology of the samples is strongly dependent on the concentration of Al. The optical property has been determined using ultraviolet visible spectrometer. The calculated value of energy band gap was obtained by the analysis of ultraviolet visible. As concentration of Al increased, the energy band gap increased. The wider band gap is a significant requirement for antireflecting coating material.