Semiconducting properties of single crystal TiO2 in the N-P transition region

This work considers the effect of ionic charge carriers on the semiconducting properties of undoped TiO2 single crystal in the n-p transition region. The semiconducting properties were characterised by using the measurements of electrical conductivity and thermoelectric power at elevated temperatures (1073-1323K) and in a gas phase of controlled oxygen activity [10 Pa < p(O2) < 75 kPa]. These data are considered in terms of the TiO2 defect disorder model. Individual conductivity components, associated with electronic and ionic charge carriers, indicate that the ionic component of electrical conductivity assumes significant values, which cannot be ignored. Its activation energy is 227 kJ/mol.