Ultra-fast and linear polarization-sensitive photodetectors based on ReSe2/MoS2 van der Waals heterostructures

Recently, van der Waals heterostructures (vdWHs) constructed by transition-metal dichalcogenides (TMDCs) have come under the research spotlight owing to their excellent capabilities, multiple functionalities, and innovative architecture for advanced optoelectronic devices. Herein, novel heterojunction photodetectors composed of monolayer molybdenum disulfide (MoS2) and few-layer rhenium selenide (ReSe2) are explored for ultra-fast and polarization detection. Owing to the enhanced light-matter interactions and type-II band alignment of the ReSe2/MoS2 heterostructure, the photodetector exhibits impressive performances at 638 nm in terms of a high on/off ratio ∼104, large photoresponsivity ∼3.52 A/W, high specific detectivity ∼1011 Jones, and large 3 dB frequency of 65.7 kHz. In addition, ultrafast rise/decay times (5.0/9.1 μs) are obtained under pulsed incident light contributed to the built-in electric field at the heterointerface, demonstrating a result one or two orders of magnitude faster than the currently reported values of group VII-TMDCs based photodetectors. Beyond the conventional photodetection, this photodetector also displays polarization detection capability with sensitivity 1.35. Such Re-based vdWHs provide superior platforms for the realization of ultra-fast and polarization-sensitive photodetection in broadband spectrum.