Effect of Oxygen Pressure During Oxidation Process on Photo-anodic Polarization of TiO₂ Films Formed by High Temperature Oxidation

Abstract

The effect of oxygen pressure during oxidation on the photo-anodic polarization behavior of TiO₂ films formed by high-temperature oxidation was investigated in a Na₂SO₄ solution. Large photoanodic currents were observed for films formed by oxidation at low oxygen pressures. The donor concentration in films increased with the decrease in oxygen pressure during oxidation. This corresponded to the increase in the photoanodic current. The increase in photoanodic current with decreasing oxygen pressure during film formation was therefore explained by the photoanodic reaction model in which the reaction proceeded through the surface state corresponding to excessive titanium ions on the film surface.