V-doped TiO2(110): Quantitative structure determination using energy scanned photoelectron diffraction

The surface structure of a novel vanadium–titanium dioxide epitaxial film (Ti1 − xVxO2, x ~ 0.2) has been explored using V4 + 2p and Ti4 + 2p energy-scanned photoelectron diffraction (PhD). The determined structure is a rutile TiO2(110)-like surface, with V atoms substitutionally replacing some Ti atoms. The results show no evidence for significant preferential occupation by V atoms of any specific surface or sub-surface sites. LEED shows a (1 × 2) reconstruction to be present on the surface, and the PhD simulations do favour this being the dominant surface termination, although the reliability factor for simulations for a (1 × 1) termination falls just within the variance of the value for the preferred (1 × 2) structure. The V3 + and Ti3 + species were observed to occupy the same sites as the V4 + and Ti4 + species; V5 + species do not appear to occupy a single well-defined structural site.