Electron beam irradiation-induced reduction of Sn on epitaxial rutile SnxTi1−xO2 alloy thin films

Epitaxially-grown SnxTi1 − xO2 alloy thin films with different compositions were fabricated by successive deposition of SnO2 on ultra-smooth Nb-doped TiO2 (rutile) (110) substrates. The surface Sn atoms of the SnxTi1 − xO2, which took a tetravalent state just after the deposition under the present condition, were reduced into a metallic state by electron beam irradiation, but not for a pure SnO2 film. The reduction process approximately obeys zero-order kinetics; the reaction rate constant linearly increases with an increase of the surface composition of Ti. Based on these results, the reduction mechanism is discussed.