Properties of fluorine-doped ZnO deposited onto glass by spray pyrolysis

Fluorine-doped ZnO (FZO) thin films were deposited onto glass by the spray pyrolysis process, using zinc acetate and NH 4F as precursors. The role of F/Zn atomic ratio, in the starting solution, and the substrate temperature were investigated and the optimum deposition conditions have been outlined. The X-ray diffraction analyses of the films show that there is incorporation of F atoms in the film. The FZO films are of polycrystalline nature with a preferential growth along (0 0 2) plane parallel to the surface of the substrate for temperatures higher than 400°C. It is observed that fluorine incorporation in the films affects the grain size, which decreases as the F/Zn atomic ratio increases, for the same substrate temperature. The films are uniform and exhibit an optical transmittance above 85% in the visible region. A critical substrate temperature (425°C) was observed at which the films show an n-type electrical dark conductivity as high as 9 (Ω cm) −1 when using a solution flow rate of 16 ml/min and a gas flow rate of 10 l/min.