Studies on structural properties of a-CN:H films prepared in electron cyclotron resonance plasma

Amorphous nitrogenated carbon films were prepared from a mixture of acetylene and nitrogen in an electron cyclotron resonance plasma and were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. In Raman spectra the ratio I_D/I_G increases by a factor of five when adding 5.5% of nitrogen in the carbon films, but unlike the previous reports, no significant shift of the G peak was noticed. Ellipsometry experiments, according to electron energy loss spectroscopy results, do not show any significant change in the π plasmon peak position but a reduction of its area was observed for the nitrogenated samples which may suggest that there was no improvement of the graphitic structure after nitrogen introduction. On the other hand, the displacement of the maximum of the N 1s peak indicates a modification in the electronic structure of the film as a function of the nitrogen concentration.