Ultrafast Self-Powered photodetector based on Plasmon-assisted InSe/WSe2 van der Waals heterostructures

Photodetectors are vital in military defense, aerospace, and imaging. Two-dimensional transition metal dichalcogenides (TMDs) attract attention for their tunable bandgap and strong light-matter interaction, but their limited thickness restricts light absorption. In this study, the influence of surface plasmon resonance and surface engineering on the InSe/WSe₂ heterostructures optoelectronic properties of the material was systematically explored by modifying the structure with gold nanoparticles (Au NPs) and functionalizing the indium film surface. By integrating Au NPs with the InSe/WSe₂ heterojunction and functionalizing the heterojunction surface using an indium layer, the device exhibited a significant enhancement in light absorption over a broadband spectral range from 447 to 1550 nm. Operating at room temperature and under zero bias voltage, the device showed a considerable improvement in optoelectronic performance compared to the pristine InSe/WSe₂ heterojunction. Specifically, the device achieved a responsivity of 1.39 A/W, a detectivity of 4.23 × 10¹¹ Jones, and an ultra-fast response time of 2.7 μs. These remarkable performance characteristics, combined with the advantages of scalable and controlled fabrication of metallic nanostructures, along with advancements in 2D material synthesis and transfer techniques, demonstrate significant potential for the large-scale, smart manufacturing of low-power, nanoscale optoelectronic devices.