RBF GE(111) INTERFACE FORMATION STUDIED BY LEED, XPS, AND UPS/

The interface formation between rubidium fluoride (RbF) and the Ge(lll )c(2x8) surface has been studied by low-energy electron diffraction, x -ray photoelectron spectroscopy, and ultraviolet photoelectron spectro scopy as a function of growth temperature. Three interface types have been identified. Sublimation of RbF at 750 R leads to a (3x1) symmetry with three domains induced by a chemisorbed submonolayer of Rb. An ep itaxial RbF overlayer is observed at 500 K with rubidium bound to the substrate (F-Rb-Ge). Island growth mode is observed at room temperatur e. A disordered layer of RbF is then formed, with two types of interfa cial bonding: Rb-F-Ge and F-Rb-Ge. The stability of the RbF film under the irradiation of various beams is also discussed.