Structure of nitrogen-substituted graphite prepared by chemical vapor deposition

The composition and structure of nitrogen-substituted graphite films formed by chemical vapor deposition were found to depend on the supply rate of the starting material, pyrrole. The supply rate was varied by changing the temperature Tm of pyrrole. X-ray diffraction indicates that the structure of the film is similar to that of graphite. Domain sizes along the basal plane La and c-axis Lc were estimated by Raman spectroscopy and X-ray diffraction respectively. As Tm was lowered, La and Lc increased. The atomic fraction of incorporated nitrogen was determined by X-ray photoelectron spectroscopy (XPS) and found to be a maximum of 12.4 at.% at Tm = 60 °C. Two peaks were observed in XPS N1s spectra at around 398 eV and 401 eV. The former was assigned to the nitrogen atoms substituted for carbon atoms in the graphite layer and the latter to those bonded to the layer edge.