Evidence for germanium segregation on thin films of Ag on Ge(111)

Ag films prepared on Ge(111) at nearly room temperature were studied with high-resolution core-level photoemission spectroscopy. By selectively modifying the sample structure to label surface sites on the Ag film, we unambiguously identified the presence of a small amount of Ge segregating on top on the growing Ag overlayer. The origin and behavior of these segregated atoms and the structure of the overlayer are discussed.