Single crystal RuO2/Ti and RuO2/TiO2 interface: LEED, Auger and XPS study

Abstract The interactions at the evolving RuO 2 /titanium interface have been studied by LEED, AES and XPS. Titanium films of up to 5 monolayers were evaporated onto well ordered and ion sputtered ruthenium dioxide crystal surfaces of (110) and (100) orientation. Stabilization of the surface oxygen content under thermal treatment in UHV (up to 600°C) with increasing titanium coverage was established. After extended (up to 4 h) annealing in O 2 at 600°C an epitaxial ordering of TiO 2 on RuO 2 (110) was observed. The (1 × 1) LEED patterns from the epitaxial layer exhibit a reduced background level when compared to the RuO 2 substrate itself. These findings are correlated with the XPS data and are interpreted in connection with the disappearance of the defect RuO 2 phase in the surface layer of the RuO 2 . The appearance of the (1 × 2) surface reconstruction at the RuO 2 (100)/Ti interface is discussed in the context of maximum cation coordination by oxygen atoms.