Let us also add what is further told in the mentioned article by Malard et al., about G, D and G' bands. The most evident bands in the Raman spectra of graphene are the "so-called G band appearing at 1582 cm -1 (graphite) and the G' band at about 2700 cm -1 using laser excitation at 2.41 eV". If we have a "disordered sample or at the edge of a graphene sample, we can also see the so-called disorder-induced D-band, at about half of the frequency of the G' band (around 1350 cm -1 using laser excitation at 2.41 eV)" . "The G band is associated with the doubly degenerate (iTO [i for in-plane] and LO) phonon mode (E2g symmetry) at the Brillouin zone center". Actually, as expressed by the authors, the G-band is "the only band coming from a normal first order Raman scattering process in graphene. On the other hand, the G' and D-bands originate from a second-order process, involving two iTO phonons near the K point for the G' band or one iTO phonon and one defect in the case of the D-band" .