Atomic origins of surface core levels on Si(111)-(7×7) studied by site-dependent Ge substitution

Abstract
Synchrotron-radiation photoemission has been used to examine the site-dependent Ge substitution for Si on Si(111)-(7×7) surfaces. The surface components of the Si 2p and Ge 3d core levels are analyzed as a function of Ge coverage and annealing temperature. The results show the lower-binding-energy component in the Si 2p core to be derived from adatom emission. Implications in regard to adatom–rest-atom charge transfer are discussed.