Room-temperature infrared detector matches performance of cryogenically-cooled devices

Feb 10, 2025

(Nanowerk News) Research Groups from Southeast University and Nanjing Normal University Achieve New Milestones in High-Performance Room Temperature Infrared Detection A research team led by Professors Zhenhua Ni and Junpeng Lv at Southeast University has recently developed a room temperature infrared detector based on a two-dimensional material vertical channel heterojunction. This advanced detector offers ultra-wideband, high-sensitivity, and high-speed infrared detection across a range from ultraviolet to mid-wave infrared. Their research has been published in Nature Communications (“High-Sensitivity, High-Speed, Broadband Mid-Infrared Photodetector Enabled by a Van Der Waals Heterostructure with a Vertical Transport Channel”). Developing a room temperature infrared detector that integrates high speed, sensitivity, and a wideband response has long been a major challenge in infrared detection. Traditional mid-wave infrared detectors face issues such as complex fabrication processes, the need for low-temperature cooling to minimize dark current, and difficulties in miniaturization and integration. In contrast, two-dimensional material heterojunction stacks avoid lattice matching constraints, span a broad range of energy bands, and are ultra-thin and flexible, making them easier to control. These materials have shown significant potential in reducing dark current at room temperature, enabling wideband detection, on-chip integration, and intelligent processing. However, despite advancements in room temperature infrared detectors using two-dimensional materials, their performance has yet to match that of commercial refrigerated infrared detectors. To address this challenge, the research teams led by Professors Zhenhua Ni and Junpeng Lv, in collaboration with Professor Hongwei Liu from the School of Physics and Technology at Nanjing Normal University, proposed a graphene/black phosphorus/molybdenum disulfide/graphene van der Waals heterojunction with a vertical channel structure. This design optimizes various performance metrics through a synergistic approach. Vertical channels offer several advantages over horizontal channels, including:

a Schematic diagram illustrating the diffusion process of photogenerated charge carriers in both vertical and lateral channel devices, with incident light directed from above onto the overlapped heterojunction region. The red and blue spheres represent holes and electrons, respectively. b Steady-state photogenerated charge carrier distribution as a function of distance from the p-n junction when excess electrons and holes are exclusively generated at the p-n junction region. Ld represents the diffusion length of the charge carriers. n0 refers to the photogenerated carrier concentration at the p-n junction region. c Comparison of the detectivity and detection range among reported room temperature-operated mid-wave infrared (MWIR) photodetectors based on 2D materials and conventional materials. The theoretical limits of D* calculated for the photodetectors operating under background-limited infrared performance (BLIP) in photovoltaic (PV) mode, photoconductive (PC) mode, and thermal infrared (TIR) mode are shown as black, red, and blue dotted lines, respectively. Tbg and FOV represent background temperature and field of review. d Comparison of the detectivity and response speed among reported room temperature-operated photodetectors based on 2D materials with MWIR (3–6 µm) responses. (Image: Courtesy of the researchers) Through collaborative optimization across multiple dimensions, the team successfully created a room temperature self-driven high-performance infrared photodetector with an impressive detection rate of up to 2.38×1011 cmHz½W-1 (approaching the theoretical limit of blackbody radiation background), a response speed of up to 10.4 nanoseconds, and a response range spanning from ultraviolet to mid-wave infrared (325 nm to 3800 nm). The performance of this detector matches that of commercial refrigeration-type mercury cadmium telluride detectors, providing valuable insights for the development of the next generation of high-performance room temperature infrared detectors.