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Room-temperature-operating highly sensitive mid-wavelength infrared (MWIR) photodetectors are utilized in a large number of important applications, including night vision, communications, and optical radar. Many previous studies have demonstrated uncooled MWIR photodetectors using 2D narrow-bandgap semiconductors. To date, most of these works have utilized atomically thin flakes, simple van der Waals (vdW) heterostructures, or atomically thin p-n junctions as absorbers, which have difficulty in meeting the requirements for state-of-the-art MWIR photodetectors with a blackbody response. Here, a fully depleted self-aligned MoS

Uncooled infrared photodetectors have evoked widespread interest in basic research and military manufacturing because of their low-cost, compact detection systems. However, existing uncooled infrared photodetectors utilize the photothermoelectric effect of infrared radiation operating at 8-12 μm, with a slow response time in the millisecond range. Hence, the exploration of new uncooled mid-wavelength infrared (MWIR) heterostructures is conducive to the development of ultrafast and high-performance nano-optoelectronics. This study explores a van der Waals heterojunction on epitaxial HgCdTe (vdWs-on-MCT) as an uncooled MWIR photodetector, which achieves fast response as well as high detectivity for spectral blackbody detection. Specifically, the vdWs-on-MCT photodetector has a fast response time of 13 ns (77 MHz), which is approximately an order of magnitude faster than commercial uncooled MCT photovoltaic photodetectors. Importantly, the device exhibits a photoresponsivity of 2.5 A/W, quantum efficiency as high as 85%, peak detectivity of 2×1010 cm Hz1/2 W-1 under blackbody radiation at room temperature, and peak detectivity of up to 1011 cm Hz1/2 W-1 at 77 K. Thereby, our work facilitates the effective design of high-speed and high-performance heterojunction uncooled MWIR photodetectors. This article is protected by copyright. All rights reserved.