Modification of C60 thin films by ion irradiation

Transformation of C-60 thin films on Si(111) substrates by irradiation with 7-MeV C-12(2+) ions is investigated. Raman-spectroscopy analysis reveals that irradiation of C-60 films at low dose causes suppression of photopolymerization. The C-60 films are transformed into a form of amorphous carbon at high dose. Slight C-60 molecules still exist in the film up to the dose of 1.1 x 10(16)/cm(2). AFM analysis shows that as-prepared insulating films become conductive after irradiation up to the dose of 1.1 x 10(16)/cm(2), which results from conductive carbon species due to dissociation of the C-60 molecule. (C) 2002 Elsevier Science B.V. All rights reserved.