Extended Fine-Structure in Secondary Backscattered Electrons

We review the structural results obtained by the analysis of the fine structure detected in the low kinetic energy range (50-400 eV) of the secondary electrons backscattered from solid surfaces. Several experiments have been performed to assess a unified picture of the physical mechanism underlying this fine structure. An interference effect experienced by the autoionized core electron seems to be the dominant channel in several materials. This allows a fruitful extension of the Auger technique to the short range structural analysis in terms of a straightforward determination of pair distribution function, disorder and thermal effects of the first few atomic layers.