Near-Ir Raman Spectroscopy of Graphitic B–C–N Materials

Raman scattering (RS) by graphitic phases BC x N ( g -BC x N), obtained by different methods, was studied using an excitation laser operating in the near-IR (NIR) range. With such excitation the most characteristic peaks for g -BC x N are 1300 cm –1 ( D -peak) and 1505 cm –1 ( G -peak). It is shown that the D - and G -peaks are associated with disordered graphite: the D -peak is observed because the selection rules change, and its intensity is correlated with the size of the graphite cluster sp 2 in a polycrystalline graphite; the G -band is associated with thegraphite mode that is RS-active in the E 2 g plane. The shift of the D -peak in g -BC x N (1300 cm –1 ) as compared with its position in graphite (1355 cm –1 ) can be explained by the positional dispersion of the D -peak with excitation wavelength. The RS line centered at 1260 cm –1 , which could be associated with a RS-active mode, is observed only for samples with high crystallinity and for RS spectra obtained at high pressures and high temperatures.