PHOTOCHEMICAL AND THERMAL EFFECTS IN LASER-IRRADIATED FULLERITE - FROM PERIODIC EXFOLIATION TO CONE FORMATION

We report a characterization of fullerite surface modification by cumu lative laser irradiation. We show that the nano-and mesostructure of t he transformed material are related and that they depend on the laser wavelength and fluence. Irradiating the sample at 1064 nm we observe p eriodic exfoliation of the transformed surface which is composed, on a nanometer scale, of a network of graphitic elongated nanoparticles. U nder UV irradiation, the nanostructure is characterized by tangled gra phene layers and cone formation is observed on a mesoscopic scale. Our observations show that different destabilization mechanisms of C-60 p roduce coalescence pathways towards different nanostructures and mesos copic morphologies. (C) 1998 American Institute of Physics.