AVS 56th International Symposium & Exhibition
    Surface Science Wednesday Sessions
       Session SS2-WeM

Paper SS2-WeM9
STM Tip Induced Surface Reactions on TiO2(110)

Wednesday, November 11, 2009, 10:40 am, Room N

Session: Surface Chemistry and Dynamics
Presenter: D.V. Potapenko, Columbia University
Authors: D.V. Potapenko, Columbia University
R.M. Osgood, Columbia University
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Chemistry on the surfaces of photocatalytic materials, including TiO2, is driven by the charge carriers that are created in the bulk of the catalyst by light adsorption. The tip of a scanning tunneling microscope may serve as an alternative source of both free electrons and holes in a semiconductor. We have studied adsorption and tip-induced surface chemistry of 4-bromobiphenyl on the TiO2(110) surface. The adsorbed molecules could be identified in the STM images at the limit of low coverages. The response of the surface to the adsorbed substance was characterized with in situ temperature program desorption. Passing the electric current from the STM tip through molecules caused dissociation of the molecules as was indicated by the changes in the STM images. We report on the conditions of the tip-induced chemistry and propose mechanistic explanation of the observed phenomena. An important follow on experiment to this work will be to examine reactions on nanocrystal TiO2.