AVS 53rd International Symposium
    Surface Science Friday Sessions
       Session SS-FrM

Paper SS-FrM10
Sputtering Induced Vacancy Cluster Formation on TiO@sub 2@(110)

Friday, November 17, 2006, 11:00 am, Room 2002

Session: Oxide Surfaces and Interfaces
Presenter: P. Karmakar, University of California, Riverside
Authors: P. Karmakar, University of California, Riverside
G.F. Liu, University of California, Riverside
J.A. Yarmoff, University of California, Riverside
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Defects and oxygen vacancies markedly affect the electronic structure and adsorption properties of metal oxides, such as TiO@sub 2@. In addition, the catalytic behavior of supported metal particles, such as Au nanoclusters, can be enhanced by defects within the substrate. In this work, defects are introduced in a controllable manner via low energy ion bombardment, and the resultant material is probed with Scanning Tunneling Microscopy (STM) and X ray Photoelectron Spectroscopy (XPS). It is shown that 0.5 keV Ar@super +@ bombardment of TiO@sub 2@(110) leads to a change of stoichiometry and the formation of mesoscopic features. XPS measurements reveal the loss of oxygen and the reduction of Ti@super 4+@ to Ti@super 3+@. STM reveals the formation of nanometer scale vacancy clusters. The instabilities initiated by sputtering lead to the formation of these structures. The process can be explained within the framework proposed by B. Kahng et al.@footnote 1@ Following significant Ar@super +@ bombardment, the cavities extend below the surface and diffuse out when the sample is annealed. Regular rectangular holes with single atomic layer steps form when sputtered TiO@sub 2@ is annealed at 880° C. @FootnoteText@ @footnote 1@ B. Kahng, H. Jeong and A. L Barabasi, Appl. Phys. Lett. 78, 805 (2001).