Gate-readout and a 3D rectification effect for giant responsivity enhancement of asymmetric dual-grating-gate plasmonic terahertz detectors

• Published in: Nanophotonics (Berlin, Germany) Vol. 12; no. 23; pp. 4283 - 4295
• Main Authors: Satou, Akira, Negoro, Takumi, Narita, Kenichi, Hosotani, Tomotaka, Tamura, Koichi, Tang, Chao, Lin, Tsung-Tse, Retaux, Paul-Etienne, Takida, Yuma, Minamide, Hiroaki, Suemitsu, Tetsuya, Otsuji, Taiichi
• Format: Journal Article
• Language: English
• Published: Berlin Walter de Gruyter GmbH 27.11.2023; De Gruyter
• Subjects: Asymmetry; Barrier layers; beyond-5g; Detectors; Diodes; Equivalence; High electron mobility transistors; high-electron-mobility transistor; Indium gallium arsenides; Nonlinearity; Plasmonics; Research centers; Semiconductor devices; Sensors; terahertz detection; Transistors; Waveforms; Wireless communication systems; Wireless communications
• ISSN: 2192-8614; 2192-8606; 2192-8614
• DOI: 10.1515/nanoph-2023-0256

Abstract We experimentally investigated the asymmetric dual-grating-gate plasmonic terahertz (THz) detector based on an InGaAs-channel high-electron-mobility transistor (HEMT) in the gate-readout configuration. Throughout the THz pulse detection measurement on the fabricated device, we discovered a new detection mechanism called the “3D rectification effect” at the positive gate bias application, which is a cooperative effect of the plasmonic nonlinearities in the channel with the diode nonlinearity in the heterobarrier between the InGaAs channel layer and the InAlAs spacer/carrier-supply/barrier layers, resulting in a giant enhancement of the detector responsivity. We also found that an undesired long-tail waveform observed on the temporal pulse photoresponse of the device is due to trapping of carriers to the donor levels in the silicon δ -doped carrier-supply layer when they tunnel through the barrier to the gate and can be eliminated completely by introducing the so-called inverted-HEMT structure. The internal current responsivity and noise-equivalent power are estimated to be 0.49 A/W (with the equivalent voltage responsivity of 4.9 kV/W with a high output impedance of 10 kΩ) and 196 pW/√Hz at 0.8 THz. These results pave the way towards the application of the plasmonic THz detectors to beyond-5G THz wireless communication systems.