Sb adsorption on TiO2(1 0 0): Growth, morphology, work function and thermal dependence

Abstract

We report a study of the deposition of antimony on TiO2(1 0 0) from sub-monolayer (ML) to more than 20 equivalent ML. The growth kinetics, the possible reaction path and the temperature dependence are characterized by ion scattering, X-ray and UV photoelectron spectroscopy and electron energy loss spectroscopy. The surface morphology at specific coverages is studied by atomic force microscopy. The results are compatible with 3D island growth since the early stages of the deposition and the absence of reduction/oxidation processes. Sb remains at the surface top without appreciable incorporation into the bulk. The islands observed for 4 and 25 equivalent ML are relatively flat attaining typical dimensions in the range of 80 to 150 nm in the base and 15 to 35 nm in height. These structures are disperse at low coverages, and closer to each other and of similar sizes at higher coverages. The thermal desorption takes place between 650 and 700 K. Exposure of the Sb/TiO2(1 0 0) surface to ambient conditions results in Sb oxidation which is removed (reduced) by annealing in the range of 500–600 K. These results could be useful in Sb ambient remediation, Sb doping of TiO2, and in the formation of Sb nanostructures on insulators.