Electron-beam damage of C60 films on hydrogen-passivated Si(100)

We report the effects of medium-energy (3.5 keV) electron-beam irradiation of C-60 films between and 4 ML thick grown on Si(100) 2x1-H studied by high-resolution electron energy-loss spectroscopy. Electron irradiation leads primarily to molecular fragmentation. Initially, molecular fragments are discrete, and saturated with hydrogen, but continued irradiation leads to the formation of a disordered material with a graphitic local structure. Experiments performed on a single monolayer of C-60 show that under irradiation, fragments can bond to the substrate via displacement or desorption of the hydrogen atoms bonded to the Si substrate. (C) 1998 American Institute of Physics.