Photovoltaic response and dielectric properties of epitaxial anatase-TiO2 films grown on conductive La0.5Sr0.5CoO3 electrodes

We have grown epitaxial anatase-TiO2 (001) films on La0.5Sr0.5CoO3 (001) bo ttom electrodes using pulsed-laser deposition. The small lattice mismatch ( 0.5%) between the anatase-TiO2 and the La0.5Sr0.5CoO3 makes it possible to grow anatase-TiO2 films with excellent crystallinity on conductive metal ox ides. The photovoltaic properties of the epitaxial anatase-TiO2 on the La0. 5Sr0.5CoO3 were characterized using a Kelvin probe. The optical band-gap en ergy was found to be 3.05 eV. The dielectric properties of the epitaxial an atase-TiO2 films were characterized using a capacitor structure of Au/anata se-TiO2/La0.5Sr0.5CoO3 on a LaAlO3 substrate. The dielectric dispersion exh ibited a power-law dependence, and the dielectric constant measured at room temperature and 1 MHz was 38. (C) 2001 American Institute of Physics.