Van der Waals/MCT heterostructure enabled high-performance uncooled mid-infrared photodetectors via synergistic suppression of dark current and interfacial recombination

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Abstract Mid-wavelength infrared (MWIR) photodetection is crucial for applications such as night vision, remote sensing, spectral imaging and optical communication, yet its room-temperature operation faces a fundamental challenge of excessive dark current. While high-operating-temperature (HOT) HgCdTe (MCT) devices mitigate this issue through band structure engineering, their practical implementation is hindered by the intricate multilayer heteroepitaxy and lattice-mismatch-induced interfacial defects. To simultaneously resolve these bottlenecks, we develop a van der Waals (vdW) heterostructure strategy by integrating two-dimensional (2D) materials with MCT. The constructed MoS 2 /graphene/MCT vdW heterostructure synergistically addresses both the dark current and interfacial constraints. The p-n junction formed across the MoS 2 /graphene/MCT induces a strong built-in electric field and potential barrier, effectively suppressing dark current. Meanwhile, the interlayer graphene minimizes trap-assisted recombination and facilitates efficient photocarrier transport. Compared with MoS 2 /MCT and graphene/MCT heterojunctions, the MoS 2 /graphene/MCT vdW photodetector achieves an order-of-magnitude improvement in specific detectivity across visible to MWIR range. The optimized device architecture demonstrates a responsivity of ~0.325 A W −1 and a peak detectivity of ~8 × 10 10 cm Hz 1/2 W −1 under room-temperature blackbody radiation, outperforming state-of-the-art uncooled MWIR photodetectors. This work provides a feasible strategy for designing high-performance uncooled MCT-based infrared photodetectors through 2D/MCT integration.

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