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

Two-dimensional materials have attracted muchinterest for realizing novel optoelectronic devices, e.g., photo-detectors. In this work, we demonstrate a high-performance black-phosphorus avalanche photodetector based on a silicon hybridplasmonic waveguide with double nanoslots, in which way the lightabsorption by black phosphorus is enhanced and the carrier transittime is reduced simultaneously. Benefiting from the avalanchemultiplication process in black phosphorus, the present waveguideavalanche photodetector exhibits high responsivities of 66 A/W(@optical power of 2.9 mu W) and 125 A/W (@optical power of 1.4 mu W) for the wavelength bands of 1.55 and 1.95 mu m, respectively.The measured 3 dB-bandwidth is 1.05 GHz, which is at least three orders of magnitude higher than those reported high-gainphotodetectors based on two-dimensional materials. The present high-performance silicon/BP waveguide avalanche photodetectorprovides a promising option toward the applications of optical sensing, optical imaging, and optical communications in thewavelength band of 1.55/1.95 mu m and even beyond.