Abstract-Asymmetric dual-grating gates graphene FET for detection of terahertz radiations

APL Photonics

J. A. Delgado-Notario, V. Clericò, E. Diez. J. E. Velázquez-Pérez. T. Taniguchi,  K. Watanabe. T. Otsuji,  Y. M. Meziani,

(a) Optical image of the ADGG-GFET and (b) zoomed image of the detector showing the central active region of the THz detector where drain (D), source (S), and top gates (TG1 and TG2) have been labeled. (c) 3D schematic view of the ADGG-GFET and (d) drain-to-source resistance vs back-gate voltage in the 4–300 K temperatures range. The charge neutrality point (CNP) was found to be close to VBG ≈ −5.8 V.

https://aip.scitation.org/doi/full/10.1063/5.0007249

A graphene-based field-effect-transistor with asymmetric dual-grating gates was fabricated and characterized under excitation of terahertz radiation at two frequencies: 0.15 THz and 0.3 THz. The graphene sheet was encapsulated between two flakes of h-BN and placed on a highly doped SiO2/Si substrate. An asymmetric dual-grating gate was implemented on the h-BN top flake. Even though no antenna was used to couple the incoming radiation, a clear gate-bias-dependent photocurrent was measured under excitation at 0.3 THz up to room temperature. We subsequently demonstrated that the device can be used for terahertz sensing and inspection of hidden metallic objects at room temperature.