IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Tuesday Sessions
       Session SS-TuA

Paper SS-TuA5
Valence Band Photoemission from Pure and Sr Diffused Single Crystal Anatase TiO@sub 2@(001) Surfaces

Tuesday, October 30, 2001, 3:20 pm, Room 121

Session: Metal Oxides: Structure and Photocatalysis
Presenter: S. Thevuthasan, Pacific Northwest National Laboratory
Authors: S. Thevuthasan, Pacific Northwest National Laboratory
V. Shutthanandan, Pacific Northwest National Laboratory
M.A. Henderson, Pacific Northwest National Laboratory
G.S. Herman, Pacific Northwest National Laboratory
S.A. Chambers, Pacific Northwest National Laboratory
Y. Liang, Pacific Northwest National Laboratory
C.H.F. Peden, Pacific Northwest National Laboratory
S. Mun, Lawrence Berkeley National Laboratory
N.M. Hamdan, Lawrence Berkeley National Laboratory
D. Shuh, Lawrence Berkeley National Laboratory
C.S. Fadley, Lawrence Berkeley National Laboratory
Correspondent: Click to Email
Single crystal rutile titanium dioxide has been extensively studied as a model oxide surface because of its commercial availability and its wide use in a variety of technological applications. In contrast, investigations of high-quality anatase titanium dioxide are limited in the literature due primarily to the lack of availability of single crystals. Recently, we have successfully grown epitaxial single crystal anatase TiO@sub 2@(001) thin films with high quality surfaces on SrTiO@sub 3@(001) substrates at the Environmental Molecular Sciences Laboratory's (EMSL) MBE facility.@footnote 1@ We have carried out valence band photoemission experiments on pure anatase TiO@sub 2@(001) thin films, and those with outdiffused Sr at the Advanced Light Source. During these experiments, we investigated the valence band region that includes the band gap and O 2p band as a function of photon energy ranging from 35 eV to 80 eV. The results were compared with those for rutile TiO@sub 2@ surfaces. Valence band spectra from sputtered and annealed (in vacuum and oxygen environments) anatase show differences compared to the valence band spectra from rutile surfaces. However, outdiffused Sr results in no visible changes to the valence band spectra. This result suggests that Sr may occupy the cation sites in a strontium titanate-like structure that exhibiting the band gap similar to the band gap of anatase titanium oxide. These results will be discussed along with the ion channeling measurements of Sr outdiffusion and substitution for cation sites. @FootnoteText@ @foontote 1@G.S. Herman, M.R. Sievers, Y. Gao, Phys. Rev. Lett. 84, 3354 (2000). Work supported by the U.S. Department of Energy, Offices of Basic Energy Sciences and Biological and Environmental Research, the Environmental Management Science Program, and the laboratory directed research and development (LDRD) program.