Near-infrared graphene photodetector enabled by plasmonic hot carrier injection from disordered percolated gold nanostructures

Abstract Near-infrared (NIR) graphene photodetectors are attractive for imaging, sensing, communication, and integrated optoelectronics, but their performance is strongly limited by the weak light absorption of graphene. Plasmonic nanostructures can enhance light–matter interaction; however, most reported devices rely on complex nano/microfabrication processes, which increases cost and limits scalability. Here, we demonstrate a NIR graphene photodetector enhanced by disordered percolated Au nanostructures through a simple fabrication process. The disordered Au nanostructures support broadband plasmonic absorption over 1200–1600 nm, producing strong local electromagnetic fields and facilitating hot-carrier generation. Spatially resolved photocurrent mapping, illumination-dependent transfer characteristics, and electromagnetic simulations support plasmon-induced hot-carrier injection from the Au nanostructures into graphene as an important contribution to the observed photoresponse. The resulting photoinduced carrier redistribution creates a potential difference between the Au-covered and uncovered graphene regions, providing the internal driving force for carrier transport at zero source–drain bias. The device exhibits a broadband zero-bias photoresponse over 1200–1600 nm, with a maximum voltage responsivity of approximately 20 mV W −1 . This work provides a simple and scalable route for low-cost plasmon-enhanced graphene NIR photodetectors.