We study the broadband optical conductivity and ultrafast carrier dynamics of epitaxial graphene in the few-layer limit. Equilibrium spectra of nominally buffer, monolayer, and multilayer graphene exhibit significant terahertz and near-infrared absorption, consistent with a model of intra- and interband transitions in a dense Dirac electron plasma. Nonequilibrium terahertz transmission changes after photoexcitation are shown to be dominated by excess hole carriers, with a 1.2 ps monoexponential decay that reflects the minority-carrier recombination time.
|Journal||Applied Physics Letters|
|Publication status||Published - 2009 Apr|