Radiation-stimulated modification of C60 films on Si-oxide surfaces

The electronic structure of C60/SiOx/Si(100) interface was studied by photoemission (valence-bands, C 1s, and Si 2p core levels) and near-edge X-ray absorption fine structure (C 1s threshold) spectroscopies. It was concluded that the SiOx/Si surface is non-reactive with respect to the interaction with C60. The exposure of the C60/SiOx/Si system under non-monochromatic synchrotron radiation causes modification of the electronic structure of this system. It is explained by polymerization of the C60 molecules and arising a strong ionic-like interaction of the polymerized C60 with the SiOx surface. Annealing of this system up to temperatures of 550-625DDGC leads to complete desorption of the C60 molecules from the non-irradiated sample areas while the modified by radiation fullerenes remain attached to the substrate.