Gallium-doped ZnO thin films deposited by chemical spray

Gallium-doped zinc oxide (ZnO:Ga) thin films were deposited on glass substrates by the spray pyrolysis technique. The effect of the variation of the [Ga]/[Zn] rate in the starting solution, the substrate temperature as well as the post-annealing treatments on the physical properties was examined. The electrical properties of the films show an improvement with the Ga incorporation and the annealing treatment. All the films were found to be polycrystalline and show a (0 0 2) preferential growth, irrespective of the deposition conditions. The films were of n-type conductivity with an electrical resistivity in the order of 8×10−3 Ω cm and optical transmittance higher than 80% in the visible region. These results makes chemically sprayed ZnO:Ga potentially applicable as transparent electrode in photovoltaic devices.