Two-pulse space-time photocurrent correlations at graphene p-n junctions reveal hot carrier cooling dynamics near the Fermi level

Abstract

Two-pulse excitation at a graphene p-n junction generates a time-dependent photocurrent response that we show functions as a novel ultrafast thermometer of the hot electron temperature, Te(t). The extracted hot electron cooling rates are consistent with heat dissipation near the Fermi level of graphene occurring by an acoustic phonon supercollision mechanism.