In this work, the properties of aluminium doped ZnO thin films grown by spray pyrolysis are presented. The structural properties of the grown thin films were characterized by X-ray diffraction (XRD). The optical properties of the grown thin films were studied using UV-visible absorption and transmission spectroscopy. The crystalline quality of the grown thin films gets degraded as the Al doping is increased. With increase in Al atomic percentage in the spray solution from 0 to about 5 %, an increase in optical transmittance along with blue-shift of the absorption edge were observed for these Al doped ZnO thin films. With increasing the Al atomic percentage above 5 %, shows a decreasing trend in the optical transmittance. The improvement in transmittance may be due to the presence of Al2O3 or other Zn-O-Al phase in the thin films [1]. The decrease in transmittance for films grown from high atomic percentage of Al may be due to the degradation in the crystallinity of the thin films. Further, Al doping did not show any noticeable change in the carrier concentration in the ZnO films indicating that Al is not acting as a dopant in the grown thin films.
