The structure of a Si(111)7 × 7:Ge interface determined by SEXAFS

Based on SEXAFS experiments, a new model for the structure of the Si(111)7 × 7: Ge interface prepared at room temperature is presented. At ~ 1 ML coverage the Ge atoms adsorb in the atop site and bond together to form chains running parallel to the surface. Additional Si chains bridge together adjacent germanium chains and terminate the structure. At higher coverages strain build-up initiates the formation of amorphous Ge.