Photo-emission electron microscopy was used to probe photon-induced O vacancies generated on (110)-(1 x 2) surfaces. An increased O vacancy concentration within the irradiated region led to an increase in local photo-electron emission. The local O-deficient region could be compensated by exposing the surface to molecular O at 10-5Torr, or via surface diffusion at 450K in vacuum. The surface diffusion coefficient was estimated to be of the order of 10-12m2/s. Photo-emission electron microscopy permitted in situ studies to be made of surface electronic defect formation and removal.

Laser-Induced Oxygen Vacancy Formation and Diffusion on TiO2 (110) Surfaces Probed by Photoemission Electron Microscopy. Xiong, G., Joly, A.G., Beck, K.M., Hess, W.P.: Physica Status Solidi C, 2006, 3[10], 3598-602