Raman scattering spectra of carbon materials used as cathodes of auto-emission radiation sources

Structured carbon materials are widely used in engineering and scientific research, in particular as materials for the auto-emission cathode of cathodoluminescent lamps. We apply Raman spectroscopy to determine the effect on fine-grained graphite (MPG-6), pyrolytic graphite, and PAN fibers when used as cathodes. Raman scattering spectra of all three materials were recorded before and after in the spectral range from 1000 to 2000 cm$^{-1}$. In addition to the main lines of G, D, and D’ of carbon materials, we found a line in the range of (1450–1460) cm$^{-1}$ in the initial pyrolytic graphite, in pyrolytic graphite after use as a cathode, and in the MPG-6 sample after use as a cathode. We observed the greatest change in the relative integral intensity of line D in pyrolytic graphite and MPG-6. This intensity increased in pyrolytic graphite and decreased in MPG-6 after use as a cathode. It will be possible to use the relative integral intensity of line D to evaluate the operation of a cathodoluminescent lamp.