Nonlinear intensity dependence of ratchet currents induced by terahertz laser radiation in bilayer graphene with asymmetric periodic grating gates

• DOI: 10.1063/5.0165248
• Publication Date: 2023-09-22T10:02:05Z
• Authors: E. Mönch; S. Hubmann; I. Yahniuk; S. Schweiss; V. V. Bel’kov; L. E. Golub; R. Huber; J. Eroms; K. Watanabe; T. Taniguchi; D. Weiss; S. D. Ganichev
• Keywords: Bilayer graphene

We report on the observation of a nonlinear intensity dependence terahertz radiation-induced ratchet effects in bilayer graphene with asymmetric dual-grating gate lateral lattices. These currents are studied structures two designs gates fabricated top boron nitride encapsulated and beneath it. The strength sign photocurrent can be controllably varied by changing bias voltages applied to individual subgates back gate. current consists contributions insensitive radiation’s polarization state, defined orientation radiation electric field vector respect metal stripes, circular sensitive helicity. show that intense results caused electron gas heating. At room temperature, saturates at high intensities order hundreds several kW cm−2. T=4 K, nonlinearity manifests itself one or orders magnitude lower; moreover, photoresponse exhibits complex intensity, including saturation even change increasing intensity. This complexity is attributed interplay Seebeck dynamic carrier-density redistribution, which feature different dependencies behavior sample’s conductivity induced latter demonstrated studying THz photoconductivity. Our study demonstrates graphene-based devices used as detectors temperature over wide range, spanning many power. Therefore, their integration together current-driven read-out electronics attractive for operation high-power pulsed sources.