Synthesis and characterization of CN thin films by IR laser deposition in a flow reactor

Carbon nitride (CNx) thin films were produced by CO2 laser (λ=10.6 µm) irradiation of mixtures containing C2H2/N2O/NH3, in a flow reactor, on Si substrates. The experimental parameters (partial concentrations of the reactants, gas flows, total pressure) were chosen in order to maximize the nitrogen incorporation in films. Chemical composition and bonding structure of the deposited films were investigated by X-ray photoelectron spectroscopy (XPS). Thus, it was found that nitrogen is chemically bonded to C sp2 or sp3 configurations, the N/C ratio (considering only the N atoms bonded to carbon) being ~20%. Scanning electron microscopy (SEM) shows a specific growth morphology, while the transmission electron diffraction (TED) and X-ray diffraction (XRD) analysis revealed that the CNx films were crystalline, with diffraction lines that matches rather well with those of the predicted β-C3N4 form