Interaction of oxygen vacancy and its impact on transmission coefficient in oxygen-deficient titanium dioxide: Ab initio calculations

摘要

Ab initio calculations on the interaction of the oxygen vacancy and its impact on the transmission coefficients in oxygen-deficient TiO2 are reported. It is found that the separated oxygen vacancies or divacancies produce partial shallow defect energy levels below the conduction-band edge as weak interactions between these vacancies. On the contrary, for the ordering oxygen divacancies, we observe that the defect energy levels fill in the bandgap. A much higher extent is found for the ordering oxygen divacancies in both columns of the supercell due to the appearance of many reduced Ti3+ ions. As a result, these oxygen divacancies expand the transmission range and improve the transmission coefficients. The microscopic origin of the oxygen-vacancy interaction is helpful to clarify the mechanism of the resistive switching phenomenon. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim