Since the theoretical prediction of A. Liu and M. Cohen about the stability of the β-C₃N₄ phase which should present a hardness comparable with that of diamond a continuing interest in carbon nitride materials has persisted. Most of the films deposited with very different preparation techniques, have shown an amorphous or disordered structure even if in some cases, small crystallites were observed embedded in the amorphous phase. Nevertheless, also non stoichiometric carbon nitride CN_x films have shown promising technological application due to their peculiar mechanical, optical and electronic properties which can be tailored as a function of the nitrogen content x.

CN_x are deposited by PLD of graphite target in presence of N₂ or mixed N₂/Ar atmosphere. Films structural and optical properties are studied by Raman spectroscopy, Ellipsometry, X-ray photoelectron and reflection electron energy loss spectroscopy, as a function of the deposition parameters (laser fluence, pressure and composition of the buffer gas, substrates temperature).