Substrate temperature dependence of ZnO films prepared by ultrasonic spray pyrolysis

Strongly c-axis oriented zinc oxide (ZnO) films were deposited on silicon wafers coated with SiO2 or 7059 coming glass substrates from a solution containing zinc acetate. The films were deposited in a hot wall reactor by the pyrolysis of an aerosol produced by an ultrasonic generator. The crystallinity, surface morphology and composition of the films were studied using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS), respectively The influences of the concentration of zinc acetate in the solution and the substrate temperature on the crystallinity of the films were studied. The films grown at a substrate temperature of 350-450 degrees C from a 0.03 M/l solution exhibited strong (002) orientation with a very smooth surface. The resistivity of the films was around 10 Omega . cm. Oxidation resulted in a 10,000-fold increase in the resistivity.