Ta-doped Anatase TiO 2 Epitaxial Film as Transparent Conducting Oxide

We present electrical transport and optical properties of Ta-doped TiO 2 epitaxial thin films with varying Ta concentration grown by the pulsed laser deposition method. The Ti 0.95 Ta 0.05 O 2 film exhibited a resistivity of 2.5×10 -4 Ω cm at room temperature, and an internal transmittance of 95% in the visible light region. These values are comparable to those of a widely used transparent conducting oxide (TCO), indium tin oxide. Furthermore, this new material falls into a new category of TCOs that utilizes d electrons.