کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5425241 | 1395851 | 2006 | 11 صفحه PDF | دانلود رایگان |

The titanium dioxide rutile (0Â 1Â 1) (equivalent to (1Â 0Â 1)) surface reconstructs to a stable (2Â ÃÂ 1) structure upon sputtering and annealing in ultrahigh vacuum. A previously proposed model (T.J. Beck, A. Klust, M. Batzill, U. Diebold, C. Di Valentin, A. Selloni, Phys. Rev. Lett. 93 (2004) 036104/1) containing onefold coordinated oxygen atoms (titanyl groups, TiO) is supported by Scanning Tunneling Microscopy (STM) measurements. These TiO sites are imaged bright in empty-states STM. A few percent of these terminal oxygen atoms are missing at vacuum-annealed surfaces of bulk-reduced samples. These O vacancies are imaged as dark spots. Their number density depends on the reduction state of the bulk. Double vacancies are the most commonly observed defect configuration; single vacancies and vacancies involving several O atoms are present as well. Formation of oxygen vacancies can be suppressed by annealing a sputtered surface first in vacuum and then in oxygen; annealing a sputtered surface in oxygen results in surface restructuring and a (3Â ÃÂ 1) phase. Anti-phase domain boundaries in the (2Â ÃÂ 1) structure are active adsorption sites. Segregation of calcium impurities from the bulk results in an ordered overlayer that exhibits domains with a centered (2Â ÃÂ 1) periodicity in STM.
Journal: Surface Science - Volume 600, Issue 19, 1 October 2006, Pages 4407-4417