INITIAL-STAGE OF C-60 FILM GROWTH AND REACTION ON SI(111) 7X7 AND GRAPHITE SURFACES STUDIED BY HREELS-STM

We have investigated the structures and the vibrational properties of C-60 thin films on Si(111) 7 X 7 and graphite surfaces by the combined measurements of high-resolution electron-energy-loss spectroscopy (HR EELS) and scanning tunnelling microscopy (STM); we refer to this combi nation as HREELS-STM. On the graphite surface, the C-60 molecules make ordered films which show asymmetric dendrite-type growth. On the Si(1 11) 7 x 7 surface, the C-60 molecules form ordered films with small do mains. At coverage lower than 1 monolayer, some of the energy-loss pea ks due to the vibrational modes of a C-60 molecule are shifted from th e bulk loss peak on both surfaces. The energy shift indicates the inte raction between C-60 molecules and the Si(111) 7 X 7 surface, and betw een C-60 molecules and the pi-orbitals of the graphite surface, respec tively.