SHIELDING EFFECTS IN OXIDES STUDIED BY LOW-ENERGY ION-SCATTERING

The atomic arrangement at the surface of oxidic compounds has often been studied by low-energy ion scattering by variation of the primary energy. For SiO2, Al2O3 and ZnO it is shown that in the energy range of 0.75-4 keV the energy dependence of the cation/anion signal ratio is essentially an intrinsic property of the target atoms and not the result of shielding of subsurface atoms. Arguments are given which indicate that this will also hold for other oxidic compounds.