Low-energy ion scattering (LEIS) for composition and structure analysis of the outer surface

The energy distribution of low-energy ions (1-2 keV) scattered at some specific angle from a solid surface, provides information on the mass, or identify, and the number of surface atoms, through the energy position and magnitude, respectively, of peaks in the spectrum. The sampling depth is restricted to one or two atom layers. In the case of single-crystal targets, surface structure or atom location information can be derived from shadowing and multiple scattering effects. Examples are included of applications to equilibrium surface segregation in alloys and the location of sulphur atoms on the Ni (001) surface. The importance of inelastic effects is discussed.