Chemical bonding of CNx films synthesized by nitrogen ion implantation into diamond and graphite

Carbon nitride films were synthesized by high-energy nitrogen ion implantation into diamond films and pyrolytic graphite at room temperature, and the chemical bonding states in implanted samples were investigated by Raman spectroscopy, infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The nitrogen and carbon in the samples were present in three different bonding states for all samples and the distribution of these states was affected by the substrate nature as well as the implantation energy. Comparison with the Raman spectra, the assignments of N 1s and C 1s bonding states in XPS for all samples were made, in which the peaks at ∼400.0 eV in N 1s spectra and ∼285.9 eV at C 1s spectra were attributed to sp2 CN bonding, whereas the peaks at ∼398.5 eV in N 1s spectra and ∼287.7 eV in C 1s spectra were ascribed to sp3 CN bonding.