Photo-excited carriers in graphene

Abstract

A linearly polarized excitation is shown to create a strongly anisotropic distribution of photo-excited carriers in graphene, where the momenta of photo-excited carriers are aligned preferentially normal to the polarization plane. This effect offers an experimental tool to generate highly directional photo-excited carriers which could assist in the investigation of "direction-dependent phenomena" in graphene-based nanostructures. The depolarization of hot photoluminescence is used to study relaxation processes in graphene, both free standing and grown on silicon carbide. This analysis is extended to include the effect of a magnetic field, thereby allowing one to obtain the momentum relaxation times of hot electrons.