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

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 equivalent toN 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 similar to 398.5 eV, and (iii) N substituted in graphite, possibly with one sp(3) carbon as a neighbor (SXAS energy similar to 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. (C) 2001 American Institute of Physics.