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

In order to investigate the strong electronic excitation effect, mainly including transformation from crystalline into amorphous state, of thin fullerite films in more detail, C-60 films were irradiated by 171.2 MeV S9+ and 120 keV H ions. The irradiated samples were analysed by means of Raman scattering and X-ray photoelectron spectroscopy (XPS) techniques. The analysis results indicated that the amorphization process of C60 films irradiated by both ions is fully dominated by electronic energy transfer. An annealing effect of strong electronic excitation, which induced the intermediate graphitization 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 destructive action of the strong electronic excitation exceeds the annealing effect, and therefore there is no intermediate graphitization process. (C) 2000 Elsevier Science B.V. All rights reserved.