Quantification of the composition of alloy and oxide surfaces using low-energy ion scattering

The influence of the chemical environment on the low-energy ion scattering (LEIS) intensities from aluminum and nickel is investigated by studying a number of different alloys (Ag80Al20, Ni80Pt20, NiAl{110}) and oxides (γ-Al2O3, α-Al2O3, α-Al2O3 sapphire {11̄02}, NiO, 14 wt % Ni/γ-Al2O3). The neutralization behavior of the He ions scattered from Al and Ni in alloys was found to be the same as for the metals. Even for the oxides, where the chemical environment of Al and Ni is radically different from that of the pure metals, the scattered ion fractions are unaffected. For NiAl{110}, however, He ions scattered from Al in the alloy show a significant lower neutralization probability in comparison to the pure Al. This was attributed to the difference in chemical environment. It will be shown that the influence of surface roughness on the LEIS-signal intensity can be quantified. Furthermore, this influence can be neglected when comparing pressed powders having different surface morphologies.