The nanoparticles of carbon were deposited from methane under the potential of a pulsed direct current discharge. The deposition was carried without external heating. The size, chemistry, and structure of carbon nanoparticles were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy. The minimum size of the nanoparticles