Characterization of Pb3Bi alloy surfaces by Auger spectroscopy and ion sputtering

The surfaces of Pb
3
Bi films obtained through evaporation on silicon substrates are analysed by using Auger Electron Spectroscopy and ion sputtering. These films reveal a strong gradient of concentration in the vicinity of the surface. In particular, the topmost layers almost exclusively contain lead, and it is only after the removal of 200 or 300 layers that the composition reaches a constant value.