Use of nitrogen atmospheric pressure plasma for synthesizing carbon nitride

Carbon nitride (CNx) with a high nitrogen content was synthesized using a nitrogen atmospheric pressure plasma. In this method, a reaction space with a high temperature and a high nitrogen content was generated. Under this condition, it was expected that a dense nitrogen radical reacting with a carbon radical would saturate carbon bonds, result in a simultaneous increase in the composition ratio (N/C), and produce a C–N single bond. The N/C ratio of the synthesized CNx reached 1.0, as determined by X-ray photoelectron spectroscopy (XPS) analysis. XPS and FT-IR analyses showed that the synthesized CNx consists of a dominant C–N bond with a C=N bond and a C≡N bond. The synthesized CNx appeared like a sphere with a diameter of about 100 nm. The optical emission of a CN radical was observed under the CNx growth conditions, and similarities and differences between a nitrogen atmospheric pressure plasma and plasma-enhanced chemical-vapor deposition were determined.