Nanostructured multiple-layer black phosphorus photodetector based on localized surface plasmon resonance

In this paper, we propose a 20-layer black phosphorus (BP) photodetector based on a nanoscale plasmonic grating structure. Different grating materials are compared to optimize the absorption. The optical characteristics of the BP photodetector are thoroughly analyzed by absorption spectra, electric intensity distribution and power flow distribution. By introducing the nanoscale plasmonic grating, the enhanced absorption can be achieved up to 89.8% at the resonance wavelength of 714 nm for p-polarized light incidence. Besides, the cut-off wavelength of the 20-layer BP photodetector is extended to the middle infrared range with a high responsitivity of 60.94 A/W. Furthermore, the dark current was also calculated to demonstrate the electric properties of the BP photodetector, and the results reveal that our BP photodetector may allow for the development of the infrared photodetectors based on two-dimensional materials.