About the G' band, since it is about twice the D band frequency, in literature we can find it also called as "2D" band. Again, let us stress that "this two-phonon band is allowed in the second order Raman spectra of graphenes without any kind of disorder or defects. In order to prevent any misleading connection of this feature with disorder or defects, and to avoid confusion between the designation of 2D to denote two dimensionality," the G' conventional notation is preferred by Malard and coworkers, 2009.