biostudies-literatureLiu CChina National Funds for Distinguished Young Scientists3821https://www.ebi.ac.uk/biostudies/studies/S-EPMC12019331biostudies-literatureUnknown16(1)Barrier detectors such as nBn and pBp architectures (formed by a n- or p-type contact layer, a barrier layer and a n- or p-type absorber) aim to block one carrier type while allowing the other to pass, but require complex hetero-integration and precise band engineering. Here, we propose an ultra-thin polar barrier strategy using a 0.75 nm water-intercalated WSe₂/H₂O/PdSe₂ heterostructure. The confined water layer forms a clean, well-ordered interface and further generates a precisely oriented polarization field that depletes electrons in WSe₂, significantly suppressing dark current to sub-pA levels across all biases, while enabling efficient tunneling of photogenerated holes. The device shows broadband photoresponse from the ultraviolet to mid-wave infrared (MWIR), with a room-temperature average detectivity exceeding 10¹⁰ cm Hz¹^/² W⁻¹ in the MWIR. It also features ultrafast response (~3 μs), polarization light sensitivity, and two-year stability. Our work establishes a platform for high-performance infrared photodetection via van der Waals gap engineering.Nature communicationsSub-pA dark current infrared photodetection enabled by polarized water-intercalated heterojunctions.PMC1201933161925403Xu PLv YChen LQin YWang FZhang SLiu XZou XLiu YLiao LTang LMa CWang PZhao SDing SZhang XLiu CWang XWang EGfalseSub-pA dark current infrared photodetection enabled by polarized water-intercalated heterojunctions.Barrier detectors such as nBn and pBp architectures (formed by a n- or p-type contact layer, a barrier layer and a n- or p-type absorber) aim to block one carrier type while allowing the other to pass, but require complex hetero-integration and precise band engineering. Here, we propose an ultra-thin polar barrier strategy using a 0.75 nm water-intercalated WSe₂/H₂O/PdSe₂ heterostructure. The confined water layer forms a clean, well-ordered interface and further generates a precisely oriented polarization field that depletes electrons in WSe₂, significantly suppressing dark current to sub-pA levels across all biases, while enabling efficient tunneling of photogenerated holes. The device shows broadband photoresponse from the ultraviolet to mid-wave infrared (MWIR), with a room-temperature average detectivity exceeding 10¹⁰ cm Hz¹^/² W⁻¹ in the MWIR. It also features ultrafast response (~3 μs), polarization light sensitivity, and two-year stability. Our work establishes a platform for high-performance infrared photodetection via van der Waals gap engineering.2025-01-01T00:00:00Z2025 Apr2025-07-10T03:08:49.499Z2025-07-10T03:08:49.499ZS-EPMC120193314026892010.1038/s41467-025-59211-5