Electrical Properties and Defect Chemistry of TiO2Single Crystal. I. Electrical Conductivity

Top Cited Papers
Publisher Website
Google Scholar
Abstract
The present work reports the electrical properties of high-purity single-crystal TiO2 from measurements of the electrical conductivity in the temperature range 1073−1323 K and in gas phases of controlled oxygen activities in the range 10-13 to 105 Pa. The effect of the oxygen activity on the electrical conductivity indicates that oxygen vacancies are the predominant defects in the studied ranges of temperature and oxygen activities. The electronic and ionic lattice charge compensations were revealed at low and high oxygen activities, respectively. The determined semiconducting quantities include: the activation energy of the electrical conductivity (Eσ = 125−205 kJ·mol-1), the activation energies of the electrical conductivity components associated with electrons (En = 218 kJ·mol-1), electron holes (Ep = 34 kJ·mol-1), and ions (Ei = 227 kJ·mol-1), and the enthalpy of motion for electronic defects (ΔHm = 4 kJ/mol). The electrical conductivity data are considered in terms of the components related to electrons, holes, and ions. The obtained data allow the determination of the n−p demarcation line in terms of temperature and oxygen activities. The band gap determined from the electronic component of the electrical conductivity is 3.1 eV.