Photovoltaic response and dielectric properties of epitaxial anatase-TiO_(2) films grown on conductive La_(0.5)Sr_(0.5)CoO_(3) electrodes

摘要

We have grown epitaxial anatase-TiO_(2) (001) films on La_(0.5)Sr_(0.5)CoO_(3) (001) bottom electrodes using pulsed-laser deposition. The small lattice mismatch (0.5) between the anatase-TiO_(2) and the La_(0.5)Sr_(0.5)CoO_(3) makes it possible to grow anatase-TiO_(2) films with excellent crystallinity on conductive metal oxides. The photovoltaic properties of the epitaxial anatase-TiO_(2) on the La_(0.5)Sr_(0.5)CoO_(3) were characterized using a Kelvin probe. The optical band-gap energy was found to be 3.05 eV. The dielectric properties of the epitaxial anatase-TiO_(2) films were characterized using a capacitor structure of Au/anatase-TiO_(2)/La_(0.5)Sr_(0.5)CoO_(3) on a LaAlO_(3) substrate. The dielectric dispersion exhibited a power-law dependence, and the dielectric constant measured at room temperature and 1 MHz was 38.