Carbon nitride thin films and nanopowders produced by CO₂ laser pyrolysis

Nanocrystalline CN_x particles and thin films were produced in a flow reactor system by the CO₂ laser pyrolysis of sensitised NH₃-N₂O-C₂H₂ reactant gas mixtures. Depending on the substrate nature (silicon or quartz) the SEM and TED analysis of the CN_x thin films revealed specific nucleation and growth morphologies of crystallites, resembling the β-C₃N₄ phase. In the case of C₃N₄ nanopowder synthesis, the relative concentration of the sensitisers (SF₆/C₂H₄) was varied to minimise SF₆ decomposition. The majority of the data obtained from powder analysis (XRD, XPS, and ir transmission measurements) suggests the presence of CN bonded phases and the formation of α- and β-C₃N₄ structures.