Polaronic trapping of electrons and holes by native defects in anatase TiO2

Benjamin J. Morgan and Graeme W. Watson
Phys. Rev. B 80, 233102 – Published 16 December 2009

Abstract

We have investigated the formation of native defects in anatase TiO2 using density functional theory (DFT) modified with on-site Coulomb terms (DFT+U) applied to both Tid and Op 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 TiO2.

  • Figure
  • Figure
  • Figure
  • Figure
  • Received 18 November 2009

DOI:https://doi.org/10.1103/PhysRevB.80.233102

©2009 American Physical Society

Authors & Affiliations

Benjamin J. Morgan* and Graeme W. Watson

  • School of Chemistry, Trinity College, University of Dublin, Dublin 2, Ireland

  • *morganb@tcd.ie
  • watsong@tcd.ie

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 80, Iss. 23 — 15 December 2009

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×