Structural characterization of Fe/Cu/Si(111) ultrathin films

摘要

Iron films of several thicknesses (1-50 monolayers, ML) were grown in ultra high vacuum conditions on Cu/Si(111) substrate. The evolution of the structural properties of the Fe films were studied by recording the polar angular behaviour of the diffracted Auger electrons in two different experimental configurations. The early stages of fcc γ-Fe(111) growth have been carefully investigated to assess the pseudomorphism of iron γ-phase. An analysis of the Auger electron diffraction (AED) patterns allows: a) to assess at 2.5-3 ML the iron film thickness at which most of the Fe atoms prefer to arrange in a bcc structure following the Kurdjmov-Sachs orientation, b) to put in evidence the existence of a few bcc arranged atomic nanostructures even for 1 monolayer (ML) iron coverage.