title: Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene.
abstract: Terahertz radiation has uses in applications ranging from security to medicine. However, sensitive room-temperature detection of terahertz radiation is notoriously difficult. The hot-electron photothermoelectric effect in graphene is a promising detection mechanism; photoexcited carriers rapidly thermalize due to strong electron-electron interactions, but lose energy to the lattice more slowly. The electron temperature gradient drives electron diffusion, and asymmetry due to local gating or dissimilar contact metals produces a net current via the thermoelectric effect. Here, we demonstrate a graphene thermoelectric terahertz photodetector with sensitivity exceeding 10 V W(-1) (700 V W(-1)) at room temperature and noise-equivalent power less than 1,100 pW Hz(-1/2) (20 pW Hz(-1/2)), referenced to the incident (absorbed) power. This implies a performance that is competitive with the best room-temperature terahertz detectors for an optimally coupled device, and time-resolved measurements indicate that our graphene detector is eight to nine orders of magnitude faster than those. A simple model of the response, including contact asymmetries (resistance, work function and Fermi-energy pinning) reproduces the qualitative features of the data, and indicates that orders-of-magnitude sensitivity improvements are possible.
authors.affiliation: Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742-4111, USA.
authors.forename: Xinghan
authors.initials: X
authors.lastname: Cai
authors.affiliation: Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742-4111, USA.
authors.forename: Andrei B
authors.initials: AB
authors.lastname: Sushkov
authors.affiliation: Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Suess
authors.affiliation: Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Mohammad M
authors.initials: MM
authors.lastname: Jadidi
authors.affiliation: Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742-4111, USA.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Jenkins
authors.affiliation: Texas A&M University, Galveston, Texas 77553, USA.
authors.forename: Luke O
authors.initials: LO
authors.lastname: Nyakiti
authors.affiliation: US Naval Research Laboratory, Washington DC 20375, USA.
authors.forename: Rachael L
authors.initials: RL
authors.lastname: Myers-Ward
authors.affiliation: Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Li
authors.affiliation: 1] Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742-4111, USA [2] Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Yan
authors.affiliation: US Naval Research Laboratory, Washington DC 20375, USA.
authors.forename: D Kurt
authors.initials: DK
authors.lastname: Gaskill
authors.affiliation: Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Murphy
authors.affiliation: Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742-4111, USA.
authors.forename: H Dennis
authors.initials: HD
authors.lastname: Drew
authors.affiliation: 1] Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742-4111, USA [2] School of Physics, Monash University, 3800 Victoria, Australia.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Fuhrer