Polarized Raman scattering in monolayer, bilayer, and suspended bilayer graphene

Polarized resonant Raman scattering studies have been performed on monolayer, bilayer, and suspended bilayer graphene. The intensity of the G band is found to be unchanged with polarization in monolayer and bilayer graphene, whereas it shows polarization dependence in suspended bilayer graphene. The 2D mode shows strong polarization depended behavior for all the samples, irrespective of layer thickness. It is found that the intensity of the 2D peak is at a maximum when the incident photon is parallel to the scattered photon and at a minimum when these are perpendicular to each other. This effect has been explained on the basis of anisotropic photon scattering through the nodes at the K-point of the Brillouin zone in graphene during optical absorption.