SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 14: 2D Materials III (joint session HL/CPP)
HL 14.1: Talk
Tuesday, March 28, 2023, 09:30–09:45, POT 81
Sub-THz detection in two dimensional systems and CVD graphene heterostructures — Franziska Linß1, Vincent Strenzke1, Pai Zhao1, Chithra S. Sharma1, Lars Tiemann1, •Qin Hua2, and Robert H. Blick1 — 1Center for Hybrid Nanostructures, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany — 2Suzhou Institute of Nanotech and Nanobionics (SINANO) of the Chinese Academy of Sciences (CAS), China
Electromagnetic radiation in the THz range can induce surface plasmons, i.e., a collective motion of electrons, in graphene-based devices. We fabricated a field-effect-transistor with asymmetric dual-grating gates (ADGG) to detect sub-THz radiation using large-scale graphene that was synthesized by chemical vapor deposition (CVD). The CVD graphene sheet is encapsulated between two flakes of hBN and placed on a highly doped Si wafer that acts as a back gate. The ADGG was structured on the top hBN flake. The control of the carrier concentration via electrostatic gates is crucial to match the resonance condition of the plasmons. The sample was characterized by sweeping the top gate voltage from -1 V to 2 V and the charge neutrality point was reached at a top gate voltage of 0.87 V at 4.2 Kelvin. Furthermore, we used a high electron mobility transistor (HEMT) to detect THz radiation, where the detection mechanism is based on a mixing with a reference radiation in a nonlinear medium. In this device, we can demonstrate sub-THz radiation at room temperature.