Nitrogen bonding structure in carbon nitride thin films studied by soft x-ray spectroscopy

Abstract

Soft x-ray absorption (SXAS) and emission (SXES) spectroscopies were applied to study the nitrogen bonding structure in magnetron sputtered CNx thin films. By comparing with calculated spectra of N in different model systems, N in three main bonding environments can be identified: (i) C≡N bonds, with a sharp SXAS peak at 399.5 eV, (ii) pyridine-like N (i.e., N bonded to two C atoms), with an x-ray absorption resonance at ∼398.5 eV, and (iii) N substituted in graphite, possibly with one sp3 carbon as a neighbor (SXAS energy ∼401 eV). These bondings are present in all CNx films analyzed; however, as shown earlier, the relative intensities between the peaks may vary with the growth conditions. Differences in the coordination of the nearest or second nearest C neighbors only cause slight changes in the peak positions and spectrum shape.

Modulation of the crystallinity of hydrogenated nitrogen-rich graphitic carbon nitrides

“…While in raw-sample, carbon is only involved in triazine cycles, the XPS N1s spectrum appears much more complex as it can be analyzed on the basis of four components suggesting then an variety of nitrogen environments as shown on Fig. 4b [19,23,28,40,42]. The main component is centered at 398.3 eV and is attributed to sp 2 N involved in C 3 N 3 cycles, the  electrons delocalization in C 3 N 3 heterocycles leading to a peak at 404.1 eV.…”

Spectroscopic Analysis of a Pulsed-Laser Deposition System for Fullerene-like Cn x Film Production

“…Nitrogen atoms can also be bonded substitutional for carbon in a graphite ring system. Peak II on 400.0-400.8 eV (PII) corresponds to the respective sp 2 C-N bonds, originating from nitrogen atoms having three neighbors [24,54]. The ratio of peaks I and II separated by approximately 2 eV, can be taken as an indicator that the microstructure of the films is fullerene-like, if the ratio of P II /P I is greater than 1 [55,56].…”

Soft X‐Ray Absorption and Emission Spectroscopy in the Studies of Nanomaterials

“…The signature changes depending on the exact local environment, and one can see a clear difference in the spectral shape among the three main N bonding structures [53,54]. One would expect a variety of second-nearest neighbor environments to be present in the film, as illustrated in the comparison between the calculated average of each subgroup (N 1 , N 2 , and N 3 ) and compare those with the experimental spectra (Figure 7.10).…”