Angle resolved photoemission measurements on AgSi(111) 7 × 7 interfaces

Abstract

The AgSi(111) interface is investigated by LEED, AES and angle resolved photoemission spectroscopy using 50 eV synchrotron radiation in p-polarization. Results on room temperature (RT) silver growth on Si(111) 7 × 7 are characterized by an evolution of the LEED pattern and of the d band shape which is consistent with 2D island formation in the submonolayer range. When the Ag coverage (Θ) is increased, a progressive build-up of Ag layers occurs with a possible interdiffusion of the atomic constituents. The ordered Si(111) 3 × 3 R(30°)Ag structure (R 3) obtained by annealing a 1 ML RT deposit gives rise to new interface states near E F. In contrast to the RT deposit at the same Θ, two well defined d band peaks are present while the bulk Si emission near 3.4 eV is clearly seen. The R 3 data would favour recent crystallographic models which conclude to an embedment of the Ag atoms in a threefold hollow adsorption site.