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
Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan.
School of Engineering, Tohoku University, Sendai, 980-8579, Japan.
Nanophotonics. 2023 Nov 9;12(23):4283-4295. doi: 10.1515/nanoph-2023-0256. eCollection 2023 Nov.
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 -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.
我们通过实验研究了基于InGaAs沟道高电子迁移率晶体管（HEMT）的栅极读出配置的非对称双光栅门等离子体太赫兹（THz）探测器。在对制造的器件进行太赫兹脉冲检测测量的过程中，我们发现在施加正栅极偏压时一种名为“三维整流效应”的新检测机制，这是沟道中等离子体非线性与InGaAs沟道层和InAlAs间隔层/载流子供应层/势垒层之间异质势垒中的二极管非线性的协同效应，从而导致探测器响应度大幅增强。我们还发现，在器件的时间脉冲光响应上观察到的不期望的长尾波形是由于载流子在隧穿势垒到达栅极时被捕获到掺硅载流子供应层中的施主能级，并且通过引入所谓的倒置HEMT结构可以完全消除这种现象。在0.8太赫兹时，内部电流响应度和噪声等效功率估计分别为0.49 A/W（等效电压响应度为4.9 kV/W，高输出阻抗为10 kΩ）和196 pW/√Hz。这些结果为等离子体太赫兹探测器在5G以上太赫兹无线通信系统中的应用铺平了道路。
