Damage of ion irradiated C60 films

Thin C-60 films deposited on clean silicon substrates were ion irradiated and subsequently investigated by using the Raman spectroscopy technique. The C-60 films were bombarded with He, N and Bi ions at energies from 30 to 800 keV and fluences in the range 10(11)less than or equal to phi less than or equal to 10(16) ions cm(-2). Our results reveal that both, the nuclear (S-n) and the electronic (S-e) energy transfers destroy the C-60 molecules. In addition it is shown that there is a well established relationship between the total energy density transfer phi(S-n + S-e) and the amount of destroyed C-60 molecules. The damage process of the C-60 starts when the total transferred energy density reaches the value required to release one atomic bond of C-60, and the destruction is completed at a transferred energy greater than or equal to 0.5 eV A(-3), which corresponds to the energy density of the C-60 molecule. (C) 1999 Elsevier Science B.V. All rights reserved.