Scanning Auger Nanoprobe (SAN)
Auger electron spectroscopy (AES) is an analytical technique for determining the elemental composition of sample surfaces to a depth of less than 10 nm. When operated in scanning mode (SAN), it is possible to map the distribution of these elements across the surface at nanoscale resolution.
The AES technique uses an electron beam to ionise core-shell electrons from atoms within a sample's surface. Relaxation of the resultant excited state leads to the emission of Auger electrons, with kinetic energies characteristic of the elements present. Variations in the kinetic energies of electrons from elements in dissimilar chemical states can be differentiated by operating the instrument at high energy resolution. Differences in chemical composition across the sample surface are mapped by scanning with a finely focussed electron beam.