Low energy ion scattering and Auger electron spectroscopy studies of clean nickel surfaces and adsorbed layers

Auger electron spectroscopy (AES) and noble gas ion scattering (IS) are applied to surface analysis in an in situ comparison of both techniques. Examples are the sorption of S and O on Ni (111). It is shown that IS allows quantitative measurements if a suitable calibration is possible. From the energy dependence of the backscattered intensity and from the surface coverage calibrated by AES an estimate of the energy dependence of the surface neutralization process becomes possible. For S and O a shadowing effect is observed, which enhances the sensitivity of IS in this case. From this shadowing effect it is concluded that the position of the adatoms is above the surface.