A NEW PREPARATION METHOD OF LAMNO3 PEROVSKITE FILM ON SRTIO3 ELECTRODE

Photoelectrochemical deposition of the LaMnO3 precursor was investigated on SrTiO3 and TiO2 single-crystal semi-conductor electrodes [(100) plane] in solutions containing Mn2+ and La3+ ions. Deposition of the LaMnO3 precursor was always observed on the SrTiO3 electrode, but not on the TiO2 electrode. Pre-electrolysis of the TiO2 electrode in solutions containing La3+ ion was necessary for the LaMnO3 precursor deposition. Thus, the LaMnO3 precursor deposition needs perovskite or perovskite-like conditions at the electrode surface. Only anodic photocurrent contributes to the LaMnO3 precursor deposition, but tunneling current does not. This suggests that OH radical produced by the photo-process is also important for the formation of the LaMnO3 precursor on the electrode. It was presumed that the LaMnO3 precursor is an amorphous LaMnO3-delta. The LaMnO3 perovskite film with a-axial orientation was formed on SrTiO3 by the heat-treatment at temperature higher than 600-degrees-C. Thus, a possibility of the epitaxial growth of LaMnO3 perovskite on SrTiO3 single-crystal electrode is demonstrated in this paper.