title: Hot carrier transport and photocurrent response in graphene.
abstract: Strong electron-electron interactions in graphene are expected to result in multiple-excitation generation by the absorption of a single photon. We show that the impact of carrier multiplication on photocurrent response is enhanced by very inefficient electron cooling, resulting in an abundance of hot carriers. The hot-carrier-mediated energy transport dominates the photoresponse and manifests itself in quantum efficiencies that can exceed unity, as well as in a characteristic dependence of the photocurrent on gate voltages. The pattern of multiple photocurrent sign changes as a function of gate voltage provides a fingerprint of hot-carrier-dominated transport and carrier multiplication.
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States. jcwsong@fas.harvard.edu
authors.forename: Justin C W
authors.initials: JC
authors.lastname: Song
authors.forename: Mark S
authors.initials: MS
authors.lastname: Rudner
authors.forename: Charles M
authors.initials: CM
authors.lastname: Marcus
authors.forename: Leonid S
authors.initials: LS
authors.lastname: Levitov
mesh_terms: D004553:Electric Conductivity; D006108:Graphite / Q000737:chemistry* / Q000528:radiation effects*; D008027:Light; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects*; D011829:Radiation Dosage
chemical_list: D006108:Graphite