title: Phonon-mediated mid-infrared photoresponse of graphene.
abstract: The photoresponse of graphene at mid-infrared frequencies is of high technological interest and is governed by fundamentally different underlying physics than the photoresponse at visible frequencies, as the energy of the photons and substrate phonons involved have comparable energies. Here, we perform a spectrally resolved study of the graphene photoresponse for mid-infrared light by measuring spatially resolved photocurrent over a broad frequency range (1000-1600 cm(-1)). We unveil the different mechanisms that give rise to photocurrent generation in graphene on a polar substrate. In particular, we find an enhancement of the photoresponse when the light excites bulk or surface phonons of the SiO2 substrate. This work paves the way for the development of graphene-based mid-infrared thermal sensing technology.
authors.affiliation: ICFO - Institut de Ciències Fotòniques , Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain.
authors.forename: M
authors.initials: M
authors.lastname: Badioli
authors.forename: A
authors.initials: A
authors.lastname: Woessner
authors.forename: K J
authors.initials: KJ
authors.lastname: Tielrooij
authors.forename: S
authors.initials: S
authors.lastname: Nanot
authors.forename: G
authors.initials: G
authors.lastname: Navickaite
authors.forename: T
authors.initials: T
authors.lastname: Stauber
authors.forename: F J
authors.initials: FJ
authors.lastname: García de Abajo
authors.forename: F H L
authors.initials: FH
authors.lastname: Koppens
keywords: graphene photodetection; graphene-phonon interaction; hot carriers; mid-infrared photodetection; surface phonon