Effects of electric field during deposition on spray deposited indium-doped zinc oxide films

Indium-doped zinc oxide (IZO) thin films were deposited on a glass substrate using spray technique with a direct current (DC) voltage applied to the nozzle to create an electric field during deposition. It was found that the presence of the electric field has a strong effect on doping efficiency, structural, electrical, and optical properties. Incorporation of indium in ZnO was confirmed by the Rutherford back scattering and X-ray diffraction peak analysis. Scanning electron microscope micrograph showed that the surface morphology changed from rice-like structure to flower-like compact structure. The electrical resistivity of IZO film prepared under the electric field was 2 × 10^-3 Ω cm, transmission in the visible region was more than about 80%, and figure of merit (Φ_TC) was 3.39 × 10^-3 Ω^-1. The films deposited under the electric field showed a band gap narrowing, which is explained using the many body effects in the perturbation theory. Spray deposited IZO film under the electric field was shown to be useful for making self-cleaning top glass in solar cell module fabrication.