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

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.