Probing the Nature of Defects of Graphene like Nano-Carbon from Amorphous Materials by Raman Spectroscopy

摘要

Raman spectral characterization of selected carbonaceous materials has been carried out at excitation wavelengths 514, 633 and 1064 nm. Raman studies exhibit the presence of G band owing to the first order of E_(2g) mode scattering, sp~3 domains at about 1355 cm~(-1) (D band) are ascribed to the disordered structures due to the on-site and hoping defects which introduces distortions in the crystal lattice. Spectral de-convolution indicates the prominence of bands namely G, D1, D2, D3 and D4. D3 and D4 bands follow Gaussian, while the others Lorentian distribution. With change in excitation wavelength of laser, the degree of dispersion of G peak and Id/Ig intensity ratio are found to increase. The crystallite size L_a. shows an inverse relation with intensity of defect to graphite band (I_d/I_g) and it also obeys Tuinstra-Koenig relation for nano-crystalline substance. The lateral size of aromatic lamellae determined using XRD analysis is in good agreement with that of Raman analysis. The feasibility of using kerosene soot, diesel soot and carbon black for electrochemical applications are also explored.