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 ({}3 ×{} {}3 -Ag or 5×{}2-Au), while it scarcely changed for a clean 7×{}7 substrate. The results are discussed in terms of the Fermi-level pinning and space-charge layers.