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The electromagnetic spectrum between microwave and infrared light is termed the "terahertz (THz) gap," of which there is an urgent lack of feasible and efficient room-temperature (RT) THz detectors. Type-II Weyl semimetals (WSMs) have been predicted to host significant RT topological photoresponses in low-frequency regions, especially in the THz gap, well addressing the shortcomings of THz detectors. However, such devices have not been experimentally realized yet. Herein, a type-II WSM (NbIrTe 4 ) is selected to fabricate THz detector, which exhibits a photoresponsivity of 5.7 × 10 4  V W -1 and a one-year air stability at RT. Such excellent THz-detection performance can be attributed to the topological effect of type-II WSM in which the effective mass of photogenerated electrons can be reduced by the large tilting angle of Weyl nodes to further improve mobility and photoresponsivity. Impressively, this device shows a giant intrinsic anisotropic conductance (σ max /σ min  = 339) and THz response (I ph-max /I ph-min  = 40.9), both of which are record values known. The findings open a new avenue for the realization of uncooled and highly sensitive THz detectors by exploring type-II WSM-based devices., (© 2022 Wiley-VCH GmbH.)

2D noble-transition-metal chalcogenides (NTMCs) are emerging as a promising class of optoelectronic materials due to ultrahigh air stability, large bandgap tunability, and high photoresponse. Here, a new set of 2D NTMC: Ta 2 PdS 6 atomic layers is developed, displaying the excellent comprehensive optoelectronic performance with an ultrahigh photoresponsivity of 1.42 × 10 6 A W -1 , detectivity of 7.1 × 10 10 Jones and a high photoconductive gain of 2.7 × 10 6 under laser illumination at a wavelength of 633 nm with a power of 0.025 W m -2 , which is ascribed to a photogating effect via study of the device band profiles. Especially, few-layer Ta 2 PdS 6 exhibits a good broadband photoresponse, ranging from 450 nm in the ultraviolet region to 1450 nm in the shortwave infrared (SIR) region. Moreover, this material also delivers an impressive electronic performance with electron mobility of ≈25 cm 2 V -1 s -1 , I on /I off ratio of 10 6 , and a one-year air stability, which is better than those of most reported 2D materials. Our studies underscore Ta 2 PdS 6 as a promising 2D material for nano-electronic and nano-optoelectronic applications., (© 2020 Wiley-VCH GmbH.)

Extreme sensitivity of room-temperature photoelectric effect for terahertz (THz) detection is demonstrated by generating extra carriers in an electromagnetic induced well located at the semiconductor, using a wrapped metal-semiconductor-metal configuration. The excellent performance achieved with THz detectors shows great potential to open avenues for THz detection., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A concept to stimulate photoconductivity in a semiconductor well below its bandgap in a metal-semiconductor-metal structure with sub-wavelength spacing is proposed. A potential well is induced in the semiconductor by external electromagnetic radiation to trap carriers from the metals. This opens an avenue to generate carriers by photons without adequate excitation energy and is expected to have great significance in modern materials., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)