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

Abstract

We report the effects of medium-energy (3.5 keV) electron-beam irradiation of ${\mathrm{C}}_{\mathrm{60}}$ films between 1 and 4 ML thick grown on Si(100) $\text{2×1-}\mathrm{H}$ 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 ${\mathrm{C}}_{\mathrm{60}}$ show that under irradiation, fragments can bond to the substrate via displacement or desorption of the hydrogen atoms bonded to the Si substrate.