| Abstract: | Carbon nitride films were prepared by an opposed-target DC reactive sputtering system and the bonding behaviors were investigated according to the nitrogen content and annealing temperature. Annealing leads to a loss of nitrogen from the films and the CN is totally removed at 600 °C. Due to annealing at 600 °C, the C---C out-of-plane vibrational band intensity at 700 cm−1 becomes very low and also the CN band at 2200 cm−1 disappears completely. The sp2 bonding in a CN compound is the most stable phase. Due to carbon's atypical nature in having its p orbital more compact and tightly bound compared to s states, the C=N sp2 phase is more stable than the C---C sp3 phase. As the C=N sp2 phase dominates the structure, the film is mainly graphite-like with some proportion of C---C, CN and N=N bonds. |
