Polaronic trapping of electrons and holes by native defects in anatase
Open Access
- 16 December 2009
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 80 (23), 233102
- https://doi.org/10.1103/physrevb.80.233102
Abstract
We have investigated the formation of native defects in anatase using density functional theory (DFT) modified with on-site Coulomb terms applied to both and states. Oxygen vacancies and titanium interstitials are found to be deep donors that trap two and four electrons, with transition levels that explain the two features seen in deep level transient spectroscopy experiments. Titanium vacancies are deep acceptors accommodating four holes. Self-trapping of both electrons and holes is also predicted. In all cases both donor and acceptor trap states correspond to strongly localized small polarons, in agreement with experimental EPR data. Variation in defect formation energies with stoichiometry explains the poor hole-trapping of reduced .
Keywords
This publication has 34 references indexed in Scilit:
- Photoinduced electron paramagnetic resonance study of electron traps in TiO2 crystals: Oxygen vacancies and Ti3+ ionsApplied Physics Letters, 2009
- Origin of magnetic moments in defectivesingle crystalsPhysical Review B, 2009
- First-principles study of native defects in anatasePhysical Review B, 2006
- Light-Induced Charge Separation in Anatase TiO2ParticlesThe Journal of Physical Chemistry B, 2005
- Photocatalytic Property and Deep Levels of Nb-doped Anatase TiO2Film Grown by Metalorganic Chemical Vapor DepostionJapanese Journal of Applied Physics, 2004
- Superior Schottky electrode of RuO2 for deep level transient spectroscopy on anatase TiO2Applied Physics Letters, 2003
- Femtosecond diffuse reflectance spectroscopy of TiO2 powdersThe Journal of Physical Chemistry, 1995
- Photocatalysis on TiO2 Surfaces: Principles, Mechanisms, and Selected ResultsChemical Reviews, 1995
- EPR study of hydrated anatase under UV irradiationThe Journal of Physical Chemistry, 1987
- Electrochemical Photolysis of Water at a Semiconductor ElectrodeNature, 1972