Swift heavy ion induced modification of C60 thin films

Modification of thin film samples of C-60 on Si and quartz substrates, induced by irradiation of 110 MeV Ni ions at various fluences, was studied. The pristine and irradiated samples were investigated using Raman spectroscopy, electrical conductivity, and optical absorption spectroscopy. The Raman data and band gap measurements indicate that swift ions at low fluences result in aggregate formations involving multiple molecular units such as dimers or polymers. High fluence irradiation results in submolecular formations and amorphous semiconducting carbon, indicating overall damage (fragmentation) of the fullerene molecules. These submolecular units in the amorphous carbon network have been identified as nanocrystalline graphite. (C) 2003 American Institute of Physics.