Applications insight into the plasmochemical state and optical properties of amorphous CNx films deposited by gas injection magnetron sputtering method

This manuscript reports the results of carbon nitride (CNx) film deposition carried out using the gas injection magnetron sputtering method. In this experiment, a pulsed gas injection was used to arrange the varying neon/nitrogen (Ne/N2) plasma discharge. This approach influences on the transition between two excitation mechanisms of plasma particles, which changed from Penning ionization to electron impact excitation, as the share of N2 pressure was increased in the range of 0.05–0.45 Pa. In relation to that outcome, the CNx (0.04 ≤ x ≤ 0.21) films presented a smoothly fluctuated chemical state, which varied from bonds hybridized in the sp1 (N ≡ C) nitrile groups, sp2 (N = C) graphite sheets, to disordered sp3 (N – C) chain structures as proved by the study of the N1s and C1s core-level spectra. These were tied up in amorphous structure arrangement, and consisted of either oxidized graphitic sheet or β-C3N4 phase, as revealed in the fast Fourier transform analysis. In conclusion, on the basis of an investigation of indiscrete optical band gap (E1g < 1.1 eV and 3.2 < E2g < 4.3 eV), the CNx were emphasized as a highly transparent (~90%) film, proving its application potential for the near-infrared devices.