The effect of Ga-doping on the structural and optical properties of ZnO thin films prepared by spray pyrolysis

In this research, zinc oxide thin films with gallium impurity have been deposited using the spray pyrolysis technique. The structural and optical properties of these films are investigated as a function of gallium doping concentrations. The ZnO and ZnO:Ga  films grown at a substrate temperature of 350 ºC with gallium doping concentrations from 1.0 to 5.0.%. The XRD analysis indicated that ZnO films have nanocrystalline wurzite structure with (002) preferential orientation and grain size varied from 39.1 to 16.1 nm. The optical properties of the thin films have been performed using UV-Vis spectrophotometer and band gap energy values are determined. The results show that the transmittance of these films was higher than 90% in the visible region and by adding Ga up to 5.0%, band gap films have been increased.