AVS 50th International Symposium
    Surface Science Thursday Sessions
       Session SS3-ThM

Paper SS3-ThM6
The Effect of Nitrogen Doping on Rutile Single Crystals - A Photochemical Surface Science Study

Thursday, November 6, 2003, 10:00 am, Room 328

Session: Oxide Structure, Growth, and Defects
Presenter: O.E. Diwald, University of Pittsburgh
Authors: O.E. Diwald, University of Pittsburgh
T.L. Thompson, University of Pittsburgh
J.T. Yates Jr., University of Pittsburgh
Correspondent: Click to Email
A major goal in the development of new materials for photocatalysis and photo electrochemistry is to shift the solid's photoresponse into the visible light region, in order to utilize solar light more efficiently. Recently, doping of polycrystalline TiO@sub 2@ with non metal ions such as nitrogen@footnote 1@ has attracted much attention, as these materials have shown activity under visible light irradiation (@lambda@ @<=@ 550 nm). In order to investigate the effect of nitrogen doping on the photoactivity of TiO@sub 2@(110) single crystals, nitrogen incorporation into the rutile lattice was achieved either by sputtering with mixtures of N@sub 2@@super +@ and Ar@super +@ ions or by thermal treatment in ammonia (NH@sub 3@). Secondary Ion Mass spectroscopy and X-ray photoelectron spectrocopy were employed to measure depth distribution and chemical state of the implanted nitrogen. For rutile single crystals, these two doping methods result in different chemical states of the incorporated nitrogen. Ion implantation by sputtering produces substitutionally bound nitride species N@super -@, whereas NH@sub 3@ treatment leads to the formation of a N-H bonded dopant in the rutile lattice. For investigation of the photoactivity, the photodesorption of O@sub 2@ was measured as a function of excitation energy and photon flux.@footnote 2@ Compared to the undoped TiO@sub 2@ (110) rutile crystal, the action curve of the crystal that was doped with substitutionally bound nitride exhibits an unexpected blueshift. These findings will be related to changes in the electronic structure of rutile TiO@sub 2@ due to the different dopant species. This work was supported by the DoD Multidisciplinary University Research Initiative (MURI) program administered by the Army Research Office under Grant DAAD-19-01-0-0619. @FootnoteText@@footnote 1@ R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga, Science, 293, 269 (2001),@footnote 2@ G. Lu, A. Linsebigler, J. T. Yates Jr., J. Chem. Phys., 102, 4657, (1995).