Fabrication of ZnO thin films by the photochemical deposition method

ZnO thin films were fabricated by the photochemical deposition (PCD) method. The deposition solution contains ZnSO4, Na2SO3, Na2S2O3 and a small amount of NH4OH for pH adjustment. We blew oxygen or oxygen + ozone (O3) gas into the solution to increase the dissolved oxygen content and enhance the oxidation reaction. The films were characterized by Auger electron and optical spectroscopy, and a photoelectrochemical (PEC) measurement. On an indium-tin-oxide (ITO) substrate, the films showed high optical transmission in the visible range. In a current–voltage measurement for films on a p-Si substrate, the O3 bubbling sample showed rectification properties and photovoltaic effects.