Self‐Driven MoS 2 /TaTe 2 /MoS 2 Heterostructure for Ultrabroadband Photodetection and on‐Chip Frequency Mixing From Terahertz to Visible

ABSTRACT Broadband photodetection from visible to terahertz (THz) wavelengths is still an issue for multipurpose optoelectronic systems. Two‐dimensional (2D) materials are promising candidates for next‐generation photodetectors (PDs), which can operate in a broad spectral domain. In this work, we report a self‐powered broadband PD based on a vertical van der Waals (vdW) heterostructure composed of a metallic TaTe 2 layer sandwiched between two semiconducting MoS 2 layers integrated with top and bottom split‐finger metallic electrodes. The device architecture enables efficient band alignment and Schottky barrier modulation, which in turn suppresses the dark current originating from metallic TaTe 2 , thereby enhancing the broadband photodetection performance at room temperature. Especially, the devised PD displays high responsivity in the THz range, reaching 11.8 A·W −1 at 0.3 THz, with a response time of 1.02 µs and a noise‐equivalent power (NEP) as low as 10.52 pW·Hz −0.5 , enabling room‐temperature THz imaging with high contrast. Beyond direct detection, the device supports frequency‐mixing and signal‐conversion functionalities with a demonstrated bandwidth exceeding 20 GHz. In the visible‐to‐near‐infrared range (∼ 638–1550 nm), a pronounced photovoltaic effect governs the device response. Self‐powered operation, room‐temperature stability, and wide‐spectrum responsivity offer a versatile optoelectronic platform for high‐speed optical transmission, multispectral imaging, and wireless energy harvesting.