High-sensitivity, high-speed, broadband mid-infrared photodetector enabled by a van der Waals heterostructure with a vertical transport channel.

The realization of room-temperature-operated, high-performance, miniaturized, low-power-consumption and Complementary Metal-Oxide-Semiconductor (CMOS)-compatible mid-infrared photodetectors is highly desirable for next-generation optoelectronic applications, but has thus far remained an outstanding challenge using conventional materials. Two-dimensional (2D) heterostructures provide an alternative path toward this goal, yet despite continued efforts, their performance has not matched that of low-temperature HgCdTe photodetectors. Here, we push the detectivity and response speed of a 2D heterostructure-based mid-infrared photodetector to be comparable to, and even superior to, commercial cooled HgCdTe photodetectors by utilizing a vertical transport channel (graphene/black phosphorus/molybdenum disulfide/graphene). The minimized carrier transit path of tens of nanometers facilitates efficient and fast carrier transport, leading to significantly improved performance, with a mid-infrared detectivity reaching 2.38 × 10 cmHzW (approaching the theoretical limit), a fast response time of 10.4 ns at 1550 nm, and an ultrabroadband detection range spanning from the ultraviolet to mid-infrared wavelengths. Our study provides design guidelines for next-generation high-performance room-temperature-operated mid-infrared photodetectors.