Titanium vacancies in nonstoichiometric TiO2 single crystal

Abstract The semiconducting properties of single‐crystal TiO 2 and their changes during prolonged oxidation at elevated temperatures and under controlled oxygen activity were monitored using measurements of electrical conductivity and thermo‐electric power. Two kinetic regimes were revealed: Regime I – rapid oxidation, associated with the transport of oxygen vacancies, and Regime II – prolonged oxidation, which corresponds to the transport of titanium vacancies. The present data represent the first documented evidence for the formation and transport of titanium vacancies in TiO 2 . This finding allows the processing of p‐type TiO 2 without the incorporation of aliovalent foreign ions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)