ADSORPTION AND DECOMPOSITION OF C-60 MOLECULES ON SI(111) SURFACES

Adsorption of C-60 molecules on Si(lll)-(7x7) has been studied using s canning tunneling microscopy under ultrahigh vacuum conditions at a va riety of temperatures and coverages. At submonolayer coverages, isolat ed C-60 molecules were found to adsorb preferentially in the areas nea r the three midadatoms within a half unit cell of (7x7) symmetry. At m onolayer coverage, the adsorbate-adsorbate interaction changes the mol ecular bonding sites and causes the local ordering of the C-60 adlayer . Thermal annealing to temperatures above 800 degrees C causes the dec omposition of C-60 molecules on the Si surface and the formation of SI C clusters. (C) 1996 American Vacuum Society.