Origin of the 2450 cm$^{-1}$ peak (G* band) in the Raman spectrum of graphene

Here, we report the Raman studies of mechanically exfoliated and chemical vapor deposited (CVD) pristine, ion{\-}irradiated, and N{\-}doped graphene (SLG, BLG, and FLG), which identify the origin of the so-called $G$*-band in graphene $\sim$ 2450 cm$^{-1}$. Our results show that the asymmetry of the $G$*-band clearly increases with interlayer stacking, with the high frequency peak exhibiting more sensitivity to intralayer defects compared to the lower component. The sub-peaks (i.e., low and high frequency components) in the $G$*{\-}band were observed to merge with increasing excitation energy and could be understood in terms of the energy dependent scattering rates of photo-excited carriers.