Properties of TiO2-based transparent conducting oxides

The development and properties of titanium dioxide (TiO2)-based transparent conducting oxides (TCO), which exhibit properties comparable to those of In2-xSnxO3 (ITO), are reviewed in this article. An epitaxial thin film of anatase Ti0.94Nb0.06O2 exhibited a resistivity (p) of 2.3 x 10(-4) Omega cm and internal transmittance of similar to 95% in the visible light region. Furthermore, we prepared polycrystalline films with p of 6.4 x 10(-4) Omega cm at room temperature on glass substrates by using sputtering. We focus on characteristics unique to TiO2-based TCO, such as a high refractive index, high transmittance in infrared, and high stability in reducing atmospheres. Possible applications of TiO2-based TCOs, as well as the mechanism of the transparent conducting properties found in this d-electron-based TCO, are discussed in this review. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim