Geomertical Structuture of the Gi/Si(111) Interface and the Si(111) (7x7) Surface

The structure of the germanium-silicon interface has been analyzed by x-ray standing waves in an ultrahigh-vacuum environment. Structural models of the Si(111) (7×7) surface have been tested through the structure and energetics of the Si(111)(7×7)-Ge interface. Our results agree with the dimer-adatom stacking-fault model of Takayanagi et al. for the bare surface. At the interface, Ge atoms occupy the atop sites on the surface atoms that offer dangling bonds as well as on the adatoms of the dimer-adatom stacking-fault model of the Si(111) (7×7) surface