Electron Beam Irradiation-Induced Reduction of SnO2 Deposited on TiO2(110) Surfaces

SnO2 was deposited by pulsed laser deposition at room temperature in ultrahigh vacuum on TiO2(110) surfaces having different chemical states, either fully oxidized TiO2(110)-(1 x 1) or partially reduced TiO2(110)-(1 x 2). For both cases, just alter deposition, Sn was found to be in an oxidized state. When the SnO2 on TiO2 surfaces was irradiated with an electron beam, SnO2 was completely reduced into a metallic state, with the reduction rate of SnO2 on the TiO2(110)-(1 x 2) surface being at least 3 times higher than that on TiO2(110)-(1 x 1). Scanning tunneling microscopy images of SnO2 on a TiO2(110)-(1 x 2) surface, measured before and after electron beam irradiation, suggest that, while SnO2 is reduced into a metal, the reduced TiO2(110)-(1 x 2) surface is simultaneously reoxidized, consequently decomposing the (1 x 2) reconstruction.