Resonant Photoemission Of Anatase Tio2 (101) And (001) Single Crystals

The resonant behavior of anatase TiO2 (101) and (001) surfaces has been investigated using synchrotron photoemission spectroscopy. The data are compared with earlier photoemission work from rutile TiO2(110) and calculations for bulk anatase in order to elucidate the degree of Ti-O hybridization in the valence band. The results for the (101) surface show good general agreement with bulk band-structure calculations. Deviations from the bulk band structure in the case of the (001) surface are attributed to the reconstruction of this surface. A small peak is observed at around 1 eV binding energy (relative to the Fermi energy) for both surfaces following the creation of surface defects (O vacancies), which is thought to arise from surface Ti3+. The attenuation of this peak by gentle heating in O-2 is attributed to healing of the surface O vacancies.