Double domain ordering and selective removal of C-60 on Ag/Si(111)-(root 3x root 3)R30 degrees

We have used ultra-high-vacuum scanning tunneling microscopy to investigate the interaction of C-60 with the Ag/Si(111)-(root 3 x root 3)R30 degrees surface. C-60 molecules bond preferentially at defect sites and step edges and form double domain islands that are ordered relative to the bulk Si in exactly the same positions as previously observed for Si(111)-7x7. We discuss the dependence of molecular packing on surface geometry and reactivity and show that the islands are removed by annealing leaving Si(111) terraces coexisting with a network of strongly bound C-60 molecules adsorbed at step edges.