V-doped TiO sub(2)(110): Quantitative structure determination using energy scanned photoelectron diffraction

The surface structure of a novel vanadium-titanium dioxide epitaxial film (Ti sub(1 - x)V sub(x)O sub(2), X ~ 0.2) has been explored using V super(4+) 2p and Ti super(4+) 2p energy-scanned photoelectron diffraction (PhD). The determined structure is a rutile TiO sub(2)(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 x 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 x 1) termination falls just within the variance of the value for the preferred (1 x 2) structure. The V super(3+) and Ti super(3+) species were observed to occupy the same sites as the V super(4+) and Ti super(4+) species; V super(5+) species do not appear to occupy a single well-defined structural site.