title: Electrical properties and defect chemistry of TiO2 single crystal. IV. Prolonged oxidation kinetics and chemical diffusion.
abstract: Measurements of both electrical conductivity and thermoelectric power were used to monitor the equilibration kinetics of undoped single-crystal TiO(2) during prolonged oxidation at 1123 and 1323 K and p(O(2)) = 75 kPa. Two kinetics regimes were revealed: kinetics regime I (rapid kinetics), which is rate-controlled by the transport of oxygen vacancies, and kinetics regime II (slow kinetics), which is rate-controlled by the transport of titanium vacancies. The incorporation of titanium vacancies allows undoped p-type TiO(2) to be processed in a controlled manner. The kinetics data were used to determine the chemical diffusion coefficient (D(chem)) associated with the transport of titanium vacancies, which is equal to D(chem) = 8.9 x 10(-14) m(2) s(-1) and D(chem) = 9.3 x 10(-15) m(2) s(-1) at 1323 and 1123 K, respectively.
authors.affiliation: Centre for Materials Research in Energy Conversion, School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia. J.Nowotny@unsw.edu.au
authors.forename: M K
authors.initials: MK
authors.lastname: Nowotny
authors.forename: T
authors.initials: T
authors.lastname: Bak
authors.forename: J
authors.initials: J
authors.lastname: Nowotny