Enhanced Electrical Conduction in Anatase TaON via Soft Chemical Lithium Insertion toward Electronics Application

Metal oxynitride semiconductors with the d0 or d10 electron configuration are promising materials for nontoxic pigments and photocatalysts, but their electrical properties have scarcely been studied. Anatase TaON (δ-TaON) is a metastable polymorph of TaON, and its epitaxial thin films show good semiconducting properties such as a wide tunability of electrical conductivity and a rather high electron mobility comparable to that of anatase TiO2. However, the density of carrier electrons (ne) provided by anion vacancies is limited to ∼1 × 1020 cm–3, so establishing a method for carrier doping of anatase TaON remains a critical issue for its use in electronics applications. In this report, we used soft chemical insertion of Li into interstitial sites of anatase TaON epitaxial thin films by using an n-butyllithium solution, and the resulting material showed a higher ne (3.5 × 1020 cm–3) than anion-deficient anatase TaON films. Additionally, the Li-inserted anatase TaON showed an enhanced Hall mobility (μH) of o...