Properties of TiO₂‐based transparent conducting oxides

Abstract

Abstract The development and properties of titanium dioxide (TiO 2 )‐based transparent conducting oxides (TCO), which exhibit properties comparable to those of In 2– x Sn x O 3 (ITO), are reviewed in this article. An epitaxial thin film of anatase Ti 0.94 Nb 0.06 O 2 exhibited a resistivity ( ρ ) of 2.3 × 10 −4 Ω cm and internal transmittance of ∼95% in the visible light region. Furthermore, we prepared polycrystalline films with ρ of 6.4 × 10 −4 Ω cm at room temperature on glass substrates by using sputtering. We focus on characteristics unique to TiO 2 ‐based TCO, such as a high refractive index, high transmittance in infrared, and high stability in reducing atmospheres. Possible applications of TiO 2 ‐based TCOs, as well as the mechanism of the transparent conducting properties found in this d‐electron‐based TCO, are discussed in this review. magnified image Photograph showing TiO 2 ‐based TCO on a transparent plastic film. Note that the film appears greenish due to interference in the film originating from its high refractive index. This high refractive index is one of the unique characteristics of TiO 2 ‐based TCO.