[18p-B2-1~15] 4.6 Terahertz Photonics

14:00 〜 14:15奨励賞エントリー英語発表

[18p-B2-3] A fast and sensitive THz rectenna detector working with zero-bias based on the 2D Dirac-Semimetal/Insulator heterostructure

〇Chao Tang^1,2, Koichi Tamura^1,3, Aoi Hamada^1,3, Hiroyoshi Kudo^1,3, Shinnosuke Uchigasaki^1,3, Yuma Takida⁴, Hiroaki Minamide⁴, Tsung-Tse Lin^1,4, Akira Satou¹, Taiichi Otsuji¹ (1.RIEC, Tohoku Univ., 2.FRIS, Tohoku Univ., 3.School of Eng. Tohoku Univ., 4.RAP, RIKEN)

キーワード：

2D material、THz detection、rectenna

In this study, we developed a fast and sensitive terahertz (THz) detector using a Bi₂Se₃/h-BN heterostructure rectenna that enables detection without a cathode-anode bias. The fabrication process involved synthesizing β-Bi₂Se₃ via vapor-controlled liquid phase growth and h-BN via chemical vapor deposition. The Bi₂Se₃ flake were cleaved and transferred onto a Si/SiO₂ substrate, followed by the deposition of anode electrodes and the hot transfer method to stack an h-BN flake, completing the fabrication with cathode and anode electrodes and a bow-tie antenna with metal pads. For THz detection, we employed a 0.95-THz, 500-mW-peak injection-seeded THz parametric generator (is-TPG) as the light source, with anode and cathode electrodes connected through a bias tee using a GSG RF probe. We observed a THz photovoltage peak of 20 mV at an applied electric field of 0.25 V/nm, with a 200-ps full width at half maximum (FWHM). This resulted in a responsivity of 40 mV/W under a 50-Ω load (equivalent to 400 V/W under a 50-kΩ load) and a response time of 100 ps (equivalent to 10 Gbps) at room temperature. Remarkably, we also achieved a responsivity of 20 mV/W at zero bias with the same response speed. The asymmetry in the peak photovoltage with respect to the applied bipolar electric field is attributed to the asymmetric Dirac conical dispersions of Bi₂Se₃, highlighting the potential for passive, high-speed THz detection using 2D semimetal devices.