Measurement of the dielectric constant of amorphous CNx films in the 0-45 eV energy range

Amorphous a-CNx thin films were deposited at room temperature by pulsed laser ablation of graphite targets in a controlled nitrogen atmosphere. By means of reflection electron-energy-loss spectroscopy their dielectric function has been obtained in the 0-45 eV energy range. An appropriate method of analysis has been also proposed which does not take into account surface contributions to the measured spectra in the presence of large electron inelastic mean free paths. The overall results show that the nitrogen introduction in the amorphous carbon matrix induces an increase in the total threefold coordination, i.e., a progressive material graphitization. This finding is also confirmed from x-ray photoelectron spectroscopy results for the N and C 1 s core levels.