An XPS study of carbon nitride synthesized by ion beam nitridation of C60 fullerene

Carbon nitride thin films were obtained using low-energy nitrogen ion beams (0.05-3.0 keV) and simultaneous sublimation of fullerene (C-60) on Si substrates. By comparing the N 1s peak positions with reference data on nitrogen containing polymers and organic molecules, it is shown that the two main components of the N 1s spectra at 400.6 and 398.5 eV correspond to nitrogen bonded to sp(2) and sp(3) carbon, respectively. It is also suggested that a third component related to ion beam-induced defects should be considered in an intermediate position (399.3 eV). This component disappears at temperatures above 500 K and reappears when the annealed samples are bombarded with Ar+ ions (1.0 keV), C 1s core level spectra do not show discrete chemical shifts but an overlapping distribution producing a broad line shape, whose centroid shifts to higher binding energies with increasing nitrogen content. The samples were determined to be amorphous by X-ray diffraction and Infrared Absorption Spectroscopy. (C) 1998 Elsevier Science S.A.