Fullerenelike arrangements in carbon nitride thin films grown by direct ion beam sputtering

Carbon nitride $(CNx)$ thin films were grown by direct $N2∕Ar$ ion beam sputtering of a graphite target at moderate substrate temperatures $(300–750K)$⁠. The resulting microstructure of the films was studied by high-resolution transmission electron microscopy. The images showed the presence of curved basal planes in fullerenelike arrangements. The achievement and evolution of these microstructural features are discussed in terms of nitrogen incorporation, film-forming flux, and ion bombardment effects, thus adding to the understanding of the formation mechanisms of curved graphitic structures in $CNx$ materials.