Hydrogenated amorphous carbon nitride (α-C∶N∶H) films were synthesized from CH4/N2, C2H4/N2 and C2H2/N2 gas mixtures using dielectric barrier discharge (DBD) plasmas.Fourier transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology, bonding structure, and composition of the α-C∶N∶H films.The influence of plasma parameters (discharge pressure in the range of 25-1000 pa, discharge frequency) on the composition and the structure of the films were systematically studied.In C2H4/N2 and C2H2/N2 systems, the deposition rate of the films was larger than that in CH4/N2 system.AFM images show that the roughness of the as-prepared films in CH4/N2 system was much more smoothness than those in C2H4/N2 and C2H2/N2 systems.From the measurement of FTIR and XPS, it was found that the films deposited with higher hydrocarbon to N2 ratio (larger than 5∶5) in the three systems included a large amount ofsp3 C-H bond, while in the lower hydrocarbon content, N-H, C=N and C=N bonds were predominately formed.Significant differences of the FTIR spectra from different carbon precursor of the as-deposited films were also observed.