Quantum material stack boosts infrared detection without cooling

Researchers have created a molybdenum disulfide/graphene/mercury cadmium telluride (MoS2/graphene/MCT) photodetector that achieves an order-of-magnitude improvement in specific detectivity across both visible and mid-wavelength infrared ranges. The device addresses a longstanding challenge in room-temperature mid-wavelength infrared detection: excessive dark current, typically caused by defects in complex multilayer structures. This new van der Waals heterostructure induces “a strong built-in electric field and potential barrier” to suppress dark current, while graphene minimizes trap-assisted recombination. The device addresses persistent challenges in room-temperature mid-wavelength infrared detection by suppressing dark current and interfacial recombination, critical factors limiting performance in uncooled sensors. Researchers designed a tri-layered van der Waals heterostructure to achieve this synergistic effect, combining interface band alignment engineering with defect passivation strategies. The core of the innovation lies in the type-II band alignment formed at the MoS2/MCT junction, enabling efficient separation of photogenerated carriers through a built-in electric field. Under illumination, minority electrons within the MCT layer are directed to the MoS2 layer with graphene acting as an assisting interlayer, maximizing photocurrent…