Theoretical phonon dispersion of graphene and Raman spectrum of large-scale graphene. The labels (G, D, 2D, etc.) identify the peaks from the Raman spectrum with the corresponding phonon energies [13–15]. Only the in-plane modes are shown since they are the only ones which are Raman active. Several Raman data-sets of graphene are shown in blue taken from different spots of the same sample at a laser wavelength of 514 nm. The red line corresponds to the average over these data-sets. The phonon dispersion is calculated using the mass of . Data adapted from [13].