Uncooled terahertz photodetectors (PDs) showing fast (ps) response and high sensitivity (noise equivalent power (NEP) < nW/Hz) over a broad (0.5-10 THz) frequency range are needed for applications in high-resolution spectroscopy (relative accuracy ∼10), metrology, quantum information, security, imaging, optical communications. However, present terahertz receivers cannot provide the required balance between sensitivity, speed, operation temperature, and frequency range. Here, we demonstrate uncooled terahertz PDs combining the low (∼2000 μm) electronic specific heat of high mobility (>50 000 cm V s) hexagonal boron nitride-encapsulated graphene, with asymmetric field enhancement produced by a bow-tie antenna, resonating at 3 THz. This produces a strong photo-thermoelectric conversion, which simultaneously leads to a combination of high sensitivity (NEP ≤ 160 pW Hz), fast response time (≤3.3 ns), and a 4 orders of magnitude dynamic range, making our devices the fastest, broad-band, low-noise, room-temperature terahertz PD, to date.
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http://dx.doi.org/10.1021/acs.nanolett.9b05207 | DOI Listing |
Sensors (Basel)
January 2025
Department of Optoelectronics, Center for Physical Sciences and Technology (FTMC), Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania.
The practical implementation of terahertz (THz) imaging and spectroscopic systems in real operational conditions requires them to be of a compact size, to have enhanced functionality, and to be user-friendly. This work demonstrates the single-sided integration of Fresnel-zone-plate-based optical elements with InGaAs bow-tie diodes directly on a semiconductor chip. Numerical simulations were conducted to optimize the Fresnel zone plate's focal length and the InP substrate's thickness to achieve constructive interference at 600 GHz, room-temperature operation and achieve a sensitivity more than an order of magnitude higher-up to 24.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
College of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, No. 1, Sub-Lane Xiangshan, Xihu District, Hangzhou, 310024, China.
The integration of mid-infrared (MIR) photodetectors with built-in encryption capabilities holds immense promise for advancing secure communications in decentralized networks and compact sensing systems. However, achieving high sensitivity, self-powered operation, and reliable performance at room temperature within a miniaturized form factor remains a formidable challenge, largely due to constraints in MIR light absorption and the intricacies of embedding encryption at the device level. Here, a novel on-chip metamaterial-enhanced, 2D tantalum nickel selenide (Ta₂NiSe₅)-based photodetector, meticulously designed with a custom-engineered plasmonic resonance microstructure to achieve self-powered photodetection in the nanoampere range is unveiled.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Yutian Road 500, Shanghai, 200083, China.
ACS Appl Mater Interfaces
January 2025
State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, P. R. China.
Terahertz (THz) emission arising from the second-order nonlinear photocurrent effects in two-dimensional quantum materials has attracted significant attention due to its high efficiency and ease of polarization manipulation. However, in centrosymmetric quantum materials, the terahertz emission is typically suppressed, caused by the directional symmetry of the photocurrent generated under femtosecond laser excitation. In this work, we report that wafer-scale type-II Dirac semimetal PtTe with lattice centrosymmetry exhibits remarkably high THz emission efficiency (2 orders of magnitude greater than that of a ZnTe nonlinear crystal with equivalent thickness) and pronounced polarization sensitivity at room temperature.
View Article and Find Full Text PDFACS Nano
December 2024
State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu-Tian Road, Shanghai 200083, China.
The demand for broadband, room-temperature infrared, and terahertz (THz) detectors is rapidly increasing owing to crucial applications in telecommunications, security screening, nondestructive testing, and medical diagnostics. Current photodetectors face significant challenges, including high intrinsic dark currents and the necessity for cryogenic cooling, which limit their effectiveness in detecting low-energy photons. Here, we introduce a high-performance ultrabroadband photodetector operating at room temperature based on two-dimensional black arsenene (b-As) nanosheets.
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