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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Organic films and electronics, photoorganics; Nanostructures; Plasmonics and nanooptics, Surface chemical reactions and heterogeneous catalysis, Surface dynamics )

O 36.87: Poster

Dienstag, 12. März 2013, 18:15–21:45, Poster B2

Probing shallow trapped electron state and related processes of TiO₂ with UHV-IRRAS — Hikmet Sezen, •Carsten Natzeck, Chengwu Yang, Alexei Nefedov, and Christof Wöll — Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

TiO₂ as a metal oxide material with a wide band gap has numerous attentions because of its distinct chemical and physical properties. The shallow trapped electron state of TiO₂ presenting ca. 0.12 eV below than the conduction band continuum has not been fully understood property that has a crucial rule about photo- and charge-induced catalytic reactions.^1,2 In this work, a novel system for infrared reflection absorption spectroscopy in ultrahigh vacuum ambience (UHV-IRRAS) was used that allows recording both UHV-IRRAS measurements at grazing incidence on single crystal and FTIR transmission measurements for polycrystalline powder samples. It has been shown, that with this system can probe directly population of presenting charges within band gap of TiO₂. Comparative studies of the shallow trapped related processes were performed under atomic hydrogen treatment and exciting stimuli are exposing UV light. Moreover, as well as the steady state, the rapid scan measurements have been done to follow dynamic of the related processes.

1) D. A. Panayotov and J. T. Yates Jr, Chemical Physics Letters 436 (1-3), 204 (2007)

2) D. M. Savory, D. S. Warren and A. J. McQuillan, The Journal of Physical Chemistry C 115 (4), 902 (2010).