Bonding structure of CNx films synthesized by nitrogen implantation into diamond films

The CNx films were synthesized by nitrogen ion (with the energy of 10 and 60 keV, respectively) implantation into diamond films. The bonding structure of the implanted films as well as diamond films was investigated using both Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). For the diamond film implanted by 10 keV nitrogen ions. Raman spectrum exhibits stronger diamond peak at 1332 cm−1 and a weak graphitic peak (G band) at 1550 cm−1, while N 1s XPS data show two main peaks at ∼398.5 and 400.0 eV, respectively. As for the diamond film implanted by 60 keV nitrogen ions, the dominant peak in N 1s XPS spectrum locates at ∼400.0 eV. Correspondingly, the graphitic peak in Raman spectrum becomes pronounced. By comparison with the Raman spectra, the assignments of C 1s and N 1s binding states in XPS for the implanted films are made, in which the peaks at ∼285.9 and 400.0 eV are attributed to CN sp2 bonding, whereas the peaks at ∼287.8 and 398.5 eV are ascribed to CN sp3 bonding.