Electron-Induced Oxygen Desorption from the TiO2(011)-2×1 Surface Leads to Self-Organized Vacancies

O. Dulub, M. Batzilln, S. Solovev, E. Loginova, A. Alchagirov, T.E. Madey, U. Diebold

1Department of Physics, Tulane University, New Orleans, Louisiana 70118, U.S.A.
2Department of Physics, University of South Florida, Tampa, FL 33620, U.S.A.
3Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, Piscataway, NJ 08855, U.S.A.

Science 317 (2007) 1052-1056

When low-energy electrons strike a titanium dioxide surface, they may cause the desorption of surface oxygen. Oxygen vacancies that result from irradiating a TiO2(011)-2x1 surface with electrons with an energy of 300 electron volts were analyzed by scanning tunneling microscopy. The cross section for desorbing oxygen from the pristine surface was found to be 9 (±6) × 10-17 square centimeters, which means that the initial electronic excitation was converted into atomic motion with a probability near unity. Once an O vacancy had formed, the desorption cross sections for its nearest and next-nearest oxygen neighbors were reduced by factors of 100 and 10, respectively. This site-specific desorption probability resulted in one-dimensional arrays of oxygen vacancies.

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Reprints available from Ulrike Diebold (diebold at iap_tuwien_ac_at).