Damage of ion irradiated C60 films

Thin C60 films deposited on clean silicon substrates were ion irradiated and subsequently investigated by using the Raman spectroscopy technique. The C60 films were bombarded with He, N and Bi ions at energies from 30 to 800 keV and fluences in the range 1011 ≤ 3D φ ≤ 3D 1016 ions cm-2. Our results reveal that both, the nuclear (Sn) and the electronic (Se) energy transfers destroy the C60 molecules. In addition it is shown that there is a well established relationship between the total energy density transfer φ(Sn + Se) and the amount of destroyed C60 molecules. The damage process of the C60 starts when the total transferred energy density reaches the value required to release one atomic bond of C60, and the destruction is completed at a transferred energy ≥ 3D 0.5 eV A-3, which corresponds to the energy density of the C60 molecule. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)