High-speed and low dark current silicon-waveguide-coupled III-V photodetectors selectively grown on SOI

Seamlessly integrating III-V active devices with Si passive components in a monolithic manner is the key for fully integrated Si photonics. In this article, we demonstrate high-performance III-V photodetectors directly grown on industry-standard (001)-oriented silicon-on-insulator (SOI) wafers and intimately coupled with Si waveguides. The Si-waveguide-coupled III-V photodetectors feature a low dark current of 60 pA corresponding to a current density of 0.002 A / c m 2 , a large photocurrent exceeding 1 mA, responsivities of 0.4 A/W at 1.3 µm and 0.2 A/W at 1.5 µm, and a large detection wavelength range over the entire telecom band. High-speed measurements reveal a 3 dB bandwidth over 52 GHz and a data communication rate of 112 Gb/s with four-level pulse-amplitude modulation and 100 Gb/s with on–off keying. The monolithic integration scheme demonstrated for III-V photodetectors in this work is also applicable to future seamless integration of III-V lasers on the Si-photonics platform.