Abstract Crystalline carbon nitride films have been synthesized on polycrystalline Ni substrates by a microwave plasma chemical vapour deposition technique, using a mixture of N 2, CH 4 and H 2 as precursor. Scanning electron microscopy shows that the film consisted of perfect crystals of short and long hexagonal bars, tetragonal bars and irregular particles. From the X-ray photoelectron spectroscopy (XPS) data, a maximum N/C ratio of 1.0 was achieved in the films. The XPS spectra of the film typically showed three peaks in the C 1s core spectrum (centered at 284.78, 285.94, and 287.64 eV) and two peaks in the N 1s core level spectrum (centered at 398.35 and 400.01 eV). This indicates that there are two types of C–N bonds; N is bonded to sp 2- or sp 3-coordinated C atoms in the as-deposited film. The X-ray diffraction pattern indicates that the film is composed of α-, β-, pseudocubic, graphitic C 3N 4 and an unidentified phase. A series of intense sharp Raman peaks were observed in the range of 100–1500 cm − 1 . These peaks match well with the calculated Raman frequencies of α- and β-C 3N 4, revealing the formation of α- and β-C 3N 4 phase.