Using isotopic self-diffusion measurements, the present work resolved a discrepancy in the literature concerning the primary oxygen-related point defect in rutile by showing that suitably prepared surfaces could controllably inject large numbers of an exceptionally mobile defect. The results strongly suggested that this defect was the oxygen interstitial, whose existence in TiO2 was predicted computationally but never experimentally confirmed. The surface pathway offered an approach for replacing donor oxygen vacancies with acceptor oxygen interstitials facilitating manipulation of near-surface electronic bands.

Surface-Based Manipulation of Point Defects in Rutile TiO2. Hollister, A.G., Gorai, P., Seebauer, E.G.: Applied Physics Letters, 2013, 102[23], 231601