Investigation of the strong electronic excitation effect in fullerite films induced by swift ions

In order to investigate the strong electronic excitation effect, mainly inc luding transformation from crystalline into amorphous state, of thin fuller ite films in more detail, C-60 films were irradiated by 171.2 MeV S9+ and 1 20 keV H ions. The irradiated samples were analysed by means of Raman scatt ering and X-ray photoelectron spectroscopy (XPS) techniques. The analysis r esults indicated that the amorphization process of C60 films irradiated by both ions is fully dominated by electronic energy transfer. An annealing ef fect of strong electronic excitation, which induced the intermediate graphi tization process before amorphization in the case of H ion irradiation, was found for the first time. But in the case of S9+ ion irradiation, the dest ructive action of the strong electronic excitation exceeds the annealing ef fect, and therefore there is no intermediate graphitization process. (C) 20 00 Elsevier Science B.V. All rights reserved.