title: Hot-Carrier Seebeck Effect: Diffusion and Remote Detection of Hot Carriers in Graphene.
abstract: We investigate hot carrier propagation across graphene using an electrical nonlocal injection/detection method. The device consists of a monolayer graphene flake contacted by multiple metal leads. Using two remote leads for electrical heating, we generate a carrier temperature gradient that results in a measurable thermoelectric voltage V(NL) across the remaining (detector) leads. Due to the nonlocal character of the measurement, V(NL) is exclusively due to the Seebeck effect. Remarkably, a departure from the ordinary relationship between Joule power P and V(NL), V(NL) ∼ P, becomes readily apparent at low temperatures, representing a fingerprint of hot-carrier dominated thermoelectricity. By studying V(NL) as a function of bias, we directly determine the carrier temperature and the characteristic cooling length for hot-carrier propagation, which are key parameters for a variety of new applications that rely on hot-carrier transport.
authors.affiliation: †ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Sierra
authors.affiliation: †ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, Bellaterra, 08193 Barcelona, Spain.|‡Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Neumann
authors.affiliation: †ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Marius V
authors.initials: MV
authors.lastname: Costache
authors.affiliation: †ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, Bellaterra, 08193 Barcelona, Spain.|§ICREA- Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain.
authors.forename: Sergio O
authors.initials: SO
authors.lastname: Valenzuela
keywords: Graphene; Seebeck effect; electron−phonon interaction; hot carriers; supercollisions