Surface electronic structure of erbium silicide epitaxially grown on Si(111)

Abstract

The determination of the electronic structure of the rare-earth (RE) silicides epitaxially grown on Si(111) is of primary importance for the understanding of the unusually low Schottky barrier height of these silicides on n-type silicon (∼ 0.35 eV). We have performed angle-resolved UV photoemission (ARUPS) experiments on ErSi1.7 epitaxially grown “in-situ” on Si(111)7 × 7 with three photon energies (He I, He II and Ne I) in the two inequivalent directions of the surface Brillouin zone (SBZ). In both directions, some peaks are found at identical initial energies - within 0.1 eV or less - for those three photons energies. Some of these “stationary structures” might be due to surface states. We shall discuss the influence of gas exposure on the ARUPS spectra. These results will be compared with those obtained on other epitaxial RE (Tb, Y) silicides.