Hydrogenated amorphous carbon synthesis by ion beam irradiation

keV ion beam irradiation at high fluence of polystyrene produces carbon films with interesting optical, electrical and mechanical properties. Very hard films with a very low energy gap of 0.6 eV or less are easily obtained with 250 keV argon beams at 1016 ions/cm2. Reflection energy loss and optical measurements have been used to study the structure and the bondings in amorphous carbon films (a-C:H) and carbon clusters of about 3 nm have been detected. The variation of the optical gap in ion irradiated polystyrene shows that a great variety of hydrogenated amorphous carbon films can be obtained by ion implantation by changing ion fluence and ion energy loss mechanism.