Electrical properties of polycrystalline TiO2. Prolonged oxidation kinetics

Abstract

The equilibration kinetics for polycrystalline TiO2 was monitored during prolonged oxidation at 1,323 K and p(O2)=75 kPa using the measurements of the electrical conductivity and thermoelectric power. The determined kinetic data indicate the presence of two kinetics regimes; the Regime I (rapid kinetics) and the Regime II (slow kinetics). The prolonged oxidation of TiO2 is considered in terms of the formation of Ti vacancies at the surface and their subsequent transport into the bulk. This effect, also observed for TiO2 single crystal, allows to obtain p-type TiO2 without the incorporation of acceptor-type foreign ions into the TiO2 lattice.