High-Speed and High-Responsivity Silicon/Black-Phosphorus Hybrid Plasmonic Waveguide Avalanche Photodetector

Two-dimensional materials have attracted much interest for realizing novel optoelectronic devices, e.g., photodetectors. In this work, we demonstrate a high-performance black-phosphorus avalanche photodetector based on a silicon hybrid plasmonic waveguide with double nanoslots, in which way the light absorption by black phosphorus is enhanced and the carrier transit time is reduced simultaneously. Benefiting from the avalanche multiplication process in black phosphorus, the present waveguide avalanche photodetector exhibits high responsivities of 66 A/W (@optical power of 2.9 μW) and 125 A/W (@optical power of 1.4 μW) for the wavelength bands of 1.55 and 1.95 μm, respectively. The measured 3 dB-bandwidth is 1.05 GHz, which is at least three orders of magnitude higher than those reported high-gain photodetectors based on two-dimensional materials. The present high-performance silicon/BP waveguide avalanche photodetector provides a promising option toward the applications of optical sensing, optical imaging, and optical communications in the wavelength band of 1.55/1.95 μm and even beyond.