Room temperature deposition of gold onto the diffuse and sharp diffraction spot Si(111)-(root 3X root 3)R30 degrees Au surfaces

Room temperature gold depositions onto Si(111)-(root 3 x root 3)R30 degrees Au surfaces with diffuse and sharp diffraction spots [Surf. Sci. 242 (1991) 73] (diffuse and sharp root 3 x root 3 Au hereafter) under UHV conditions has been monitored using transmission electron diffraction (TED). Both systems display an increase in surface structure diffraction spot intensities up to the completion of 1.0 monolayer (ML) after which the surface beams display an exponential decrease in intensity with coverage, The exponential decay rate decreases after roughly 1.33 ML. These results can be attributed to gold initially diffusing to and filling root 3 x root 3 Au gold trimer sites in vacancy type surface domain walls [Surf. Sci. 342 (1995) 233], then filling one of three possible sites on the root 3 x root 3 Au structure with essentially no surface diffusion, disrupting nearby gold trimers. Gold deposition onto the diffuse type structure caused the formation and expansion of satellite arcs around the strongest root 3 x root 3 beams similar to those seen by others [Surf. Sci. 242 (1991) 73; Jpn. J. Appl. Phys. 16 (1977) 891; J. Vac. Sci, Technol, A 10 (1992) 3456] at elevated temperatures while the sharp structure displayed only a modest shoulder formation near the strongest root 3 x root 3 beams.