Ion beam studies of oxygen exposed Ni(100)

Abstract

A clean Ni(100) surface and a surface exposed to 18O2, have been studied by high-energy ion scattering and nuclear reaction analysis. The structure of the clean and the exposed surfaces is studied by 750 keV He+ ion scattering in combination with channeling and blocking. The results are consistent with results obtained by medium-energy ion scattering. Absolute oxygen contents are measured using the 18O(p, α)15N nuclear resonance at Ep=1766 keV. It is found that the oxygen content of the surface for which the c(2×2) LEED pattern is observed, is 0.42±0.04 of a Ni(100) monolayer. The oxygen content of a saturated oxide layer is 2.4±0.2 of a monolayer. Furthermore, it is concluded that the saturated oxide layer consists of stoichiometric NiO.