Localized Surface Plasmon Resonance Enables Si-Based Near-Infrared Photodetector

Compared with silicon (Si), 2D-graphene is a promising candidate for broadband photodetection. However, its flat surface and extremely low light absorption properties severely inhibit the device’s performance. Herein, we propose a Si-based near-infrared (NIR) photodetector integrated with 3D-graphene and silver nanoparticles (Ag-NPs). The synergy mechanism of surface plasmon polaritons induced by Ag-NPs and the natural nano-resonator of 3D-graphene can facilitate light absorption, enhance the built-in electric field, and improve the photoelectric performance. In addition, the enhancement of the local electric field by the localized surface plasmon resonance (LSPR) effect of Ag-NPs was explored using finite-difference-time-domain (FDTD) simulations. The as-fabricated photodetector exhibits ultrahigh responsivity (65.3 A/W) and ideal specific detectivity (1.5 <tex-math notation="LaTeX">× \,\,10^10 </tex-math> Jones) under the communication wavelength (1550 nm). The photodetectors feature ultrafast response times (245/ <tex-math notation="LaTeX">185~μ s </tex-math> rise/fall times), good reproducibility, and long-term durability. The photo-response mechanism was probed by first-principles density functional theory (DFT) simulation. This work demonstrates the potential of 3D-graphene with integrated metallic nanomaterials to fabricate NIR photodetectors.