X‐ray photoelectron spectroscopy study of carbon nitride coatings deposited by IR laser ablation in a remote nitrogen plasma atmosphere

Abstract

The reactive pulsed laser deposition technique was used to deposit carbon nitride .CN x / coatings on a silicon substrate. In this process, an infrared transversely excited atmospheric pressure CO 2 laser ablation of a graphite target in a remote nitrogen plasma afterglow was used to provide simultaneously both carbonand nitrogen-containing species. Evidence of different CN bonding configurations has been observed in the deposited coatings. For nitrogen pressures (P N 2 ) of ≥700 Pa there is an increase in the contribution of sp 2 carbon atoms that is associated with graphitization of the CN x coatings. For P N 2 increasing from zero to 100 Pa, the comparison between XPS core-level and valence band spectra of the CN x coatings shows good correlation between the p-derived states (C 2p electrons) of C-C p bonds in the valence band and the sp 2 carbon atom concentration deduced from the C 1s spectra.The progressive positive contribution of nitrogen lone pair electrons to the valence band is consistent with the increase of the N-C sp 3 contribution with P N 2 . The decrease in the sp 2 carbon atom contribution is associated with the increase of the nitrogen concentration in the coatings.

Effect of Nitrogen Plasma Afterglow on Amorphous Carbon Nitride Thin Films Deposited by Laser Ablation

“…Figure 4 shows the XPS C 1s and N 1s core level spectra of carbon nitride films (series I and II) prepared at various nitrogen pressures. In the two cases (series I and II) the C 1s spectra show asymmetric broad peaks, which indicate to the presence of different types of bonds in the deposited films [22,[45][46][47].…”

“…1. More details about the technique and deposition procedures are explained in previous works [22,29]. To investigate the structure and composition of the films, different techniques are used.…”

“…Although XPS analysis is used extensively to study carbon nitride films for the characterization of bond types and the chemical local environment around C, N and O of CN phases, there were some controversies about the assignments of the individual components of C 1s and N 1s core level spectra in the literature [22,45]. Figure 4 shows the XPS C 1s and N 1s core level spectra of carbon nitride films (series I and II) prepared at various nitrogen pressures.…”

“…From these results, the increase of nitrogen content in the films using microwave NPA could be ensured. Table summarizes elemental In this work, for the purpose of investigating the bonding configurations of carbon and nitrogen atoms in our a-CN x films, both C 1s and N 1s spectra were deconvoluted into six and three Gaussian-Lorentzian line shapes respectively, as illustrated in detail on previous XPS study [22].…”

“…the protective overcoat layer for magnetic thin-film rigid disks [17,18]. These interesting properties seem to be attributed to the bonding state of a-CN x films and their specific microstructure, which depends strongly on the deposition conditions, and may contain different configurations of bonds (sp 1 , sp 2 and sp 3 ) [19][20][21][22]. Therefore, studying the structural characteristics of these films is highly important to understand their physical properties.…”