Zinc oxide thin films by spray pyrolysis method

ZnO thin films were deposited by spraying of zinc acetate solution onto heated glass substrates at 670 K. Highly textured in the (002) direction undoped ZnO films, exhibiting exciton emission bands in photoluminescence spectra at 8 K, were grown. The initial stages of the thin film growth and effect of doping with In, Ce and Eu were studied. A spraying time of 30 s leads to continuous crystalline films with well-shaped grains with narrow granulometric distribution and mean grain size close to 35 nm. Depositing times longer than 2 min lead to the solid phase sintering process. Wide granulometric distribution of the grains in the range of 50-400 nm was found for undoped films. It is shown that the size and orientation of crystallites in the film, the optical and electrical properties of the films are determined by the dopant concentration. As a result dense ZnO films with high optical transmittance were produced.