Van der Waals/MCT Heterostructure Enabled High-Performance Uncooled Mid-Infrared Photodetectors via Synergistic Suppression of Dark Current and Interfacial Recombination

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 heterostructure strategy by integrating 2D materials with MCT. The constructed MoS₂/graphene/MCT vdW heterostructure synergistically addresses both the dark current and interfacial constraints. The p-n junction formed across the MoS₂/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 MoS₂/MCT and graphene/MCT heterojunction, the MoS₂/graphene/MCT vdW photodetector achieves an order-of-magnitude improvement in detectivity across visible to MWIR range. The optimized device architecture demonstrates a responsivity of ~ 0.35 A W⁻ ¹ and a peak detectivity of ~ 8 × 10¹⁰ cm Hz1/2 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 photodetector through 2D/MCT integration.