Photoelectrochemical effects of BaTiO3 thin film electrodes prepared by the sol-gel method

Abstract

The photoelectrochemical properties of La3+-doped BaTiO3 thin film electrodes prepared by the sol-gel method have been investigated as a function of the amount of La3+ content, film thickness, heating atmosphere (air/H2), and optical absorption. In the air-heated electrodes doped with 0.1, 0.2, and 0.3 mol % La3+, the maximum quantum efficiencies have been obtained when the film thicknesses were 10 000, 8000, and 3000 Å, respectively. When the film thicknesses are over certain absorption depths, whose calculated values are over 10 000, 8000, and 6500 Å, respectively, their quantum efficiencies decrease. In the hydrogen-heated electrodes, the depletion layer decreases as the donor concentration increases, and the optical absorption edge moves to longer wavelength by 0.07 eV. Also, the quantum efficiency decreases as the film thickness increases due to the bulk recombination.