High-Sensitivity Broadband Terahertz Detection Enabled by Synergistic Effect in Antenna-Integrated TaCo2Te2/Graphene Heterostructure

Abstract

A van der Waals (vdW) heterostructure based on the semimetals TaCo₂Te₂ and graphene is fabricated with an integrated fan-shaped conductive antenna and has been investigated for terahertz (THz) detection at room temperature. Assisted with the fan-shaped conductive antenna, the vdW detector exhibits high sensitivity and a broadband detection from 0.02 to 0.34 THz, which is driven by the synergistic effects of the photothermoelectric effect in the self-powered mode and the photoconductive effect when applying a bias voltage. Thanks to the efficient energy transfer and the optimized photothermoelectric characteristics in the asymmetry architecture, the detector presents a responsivity of 1.30 V/W with a noise-equivalent power (NEP) of 340 pW/Hz^1/2 and a response time of 350/250 µs, measured at 0.1 THz in the self-powered mode. By applying a bias voltage of -0.1 V, the detector achieves a much higher responsivity of 80.98 V/W and a NEP of 23 pW/Hz^1/2 at the resonant frequency of 0.331 THz, boosted by dramatically enhanced carrier concentration in the photoconductive process. The excellent optoelectronic properties of the TaCo₂Te₂/graphene heterostructure demonstrated by our study could be further explored for the development of high-sensitivity broadband THz detectors.