Initial stage of C₆₀ film growth and reaction on Si(111)7×7 and graphite surfaces studied by HREELS-STM

We have investigated the structures and the vibrational properties of C₆₀ thin films on Si(111)7×7 and graphite surfaces by the combined measurements of high-resolution electron-energy-loss spectroscopy (HREELS) and scanning tunnelling microscopy (STM); we refer to this combination as HREELS-STM. On the graphite surface, the C₆₀ molecules make ordered films which show asymmetric dendrite-type growth. On the Si(111)7×7 surface, the C₆₀ molecules form ordered films with small domains. At coverage lower than 1 monolayer, some of the energy-loss peaks due to the vibrational modes of a C₆₀ molecule are shifted from the bulk loss peak on both surfaces. The energy shift indicates the interaction between C₆₀ molecules and the Si(111)7×7 surface, and between C₆₀ molecules and the πr-orbitals of the graphite surface, respectively.