Structural, optical and electrical properties of ZnO and ZnO-Al2O3 films prepared by dc magnetron sputtering

ZnO and ZnO-Al2O3 thin films were prepared by de magnetron sputtering and t heir structural, optical and electrical properties were studied comparative ly. It is discovered that the ZnO-Al2O3 thin films remain transparent in a shorter wavelength range than the ZnO films, resulting from the increase of their band gap. Their resistivity decreases by seven orders of magnitude, which is caused by doping of Al to ZnO grains in the film. Preferential ori entation of ZnO grains in the ZnO-Al2O3 thin films deteriorates because of the existence of Al2O3 impurity phase in the film.