SURFACE-STRUCTURES AND CONDUCTANCE AT EPITAXIAL GROWTHS OF AG AND AU ON THE SI(111) SURFACE

In situ measurements of surface conductance, combined with simultaneous observations of reflection high-energy electron diffraction, clearly demonstrated strong dependence of the conductance on substrate-surface structures and epitaxial growth styles at early stages of Ag and Au depositions on Si(111) surface at room temperature. The conductance showed a large change with a small amount of deposition (< 0.1 monolayer) on the substrate of a metal-induced superstructure (square-root 3 x square-root 3-Ag or 5 x 2-Au), while it scarcely changed for a clean 7 x 7 substrate. The results are discussed in terms of the Fermi-level pinning and space-charge layers.