Intermixing at the early stage of the Si(111)/Ag interface growth

A synchrotron radiation (SR) photoemission investigation of the Si(111) cleaved surface+Ag thin overlayers (0.25-2.5 monolayers (ML) has been carried out at room temperature with the Cooper minimum method and at liquid nitrogen temperature (LNT) for a critical coverage (0.5 ML) with the energy dependent escape depth method. The two experiments give independent evidences of intermixing, following chemical reaction, between Ag and Si at the very low coverages, indicating that the very early stage of the Si(111)/Ag junction is not a sharp interface but an intermixed region extended to at least two layers of material.