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

• Published in: Science (American Association for the Advancement of Science) 2007-08, Vol.317 (5841), p.1052-1056
• Main Authors: Dulub, Olga, Batzill, Matthias, Solovev, Sergey, Loginova, Elena, Alchagirov, Alim, Madey, Theodore E., Diebold, Ulrike
• Format: Article
• Language: English
• Subjects: Atoms; Augers; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Desorption; Diet; Electron and ion emission by liquids and solids; impact phenomena; Electrons; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Ions; Lead; Oxides; Oxygen; Photon- and electron-stimulated desorption; Physics; Radiation; Scanning electron microscopy; Urelements
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1144787

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)-2×1 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 neighbours were reduced by factors of 100 and 10, respectively. This site-specific desorption probability resulted in one-dimensional arrays of oxygen vacancies.