Luminescence of graphene

Graphene emits luminescence. Due to its unique properties, the luminescence of graphene can be controlled in spectral and temporal aspects. The steep energy dispersion relation of electrons results in a low density of states and low specific heat. Current- and photo-excitations readily achieve a high electron temperature, leading to a wide spectral range of luminescence extending to the visible and ultraviolet regions. The low density of states enables control of the Fermi energy over a range of several hundred millielectronvolts through electron and hole doping, resulting in a highly controllable spectrum. The ultrathin thickness allows graphene to be aligned with various structures, such as trench substrates and photonic crystals, to control the luminescence spectrum using interference. The low dimensionality strengthens the screened Coulomb interactions between electrons and holes. This leads to the appearance of a Fermi edge singularity in the luminescence due to many-body electron-hole interactions. This review introduces the luminescence of graphene and various control techniques, as well as future research directions.