High-performance silicon-graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm

• Published in: Light, science & applications Vol. 9; no. 1; p. 29
• Main Authors: Guo, Jingshu, Li, Jiang, Liu, Chaoyue, Yin, Yanlong, Wang, Wenhui, Ni, Zhenhua, Fu, Zhilei, Yu, Hui, Xu, Yang, Shi, Yaocheng, Ma, Yungui, Gao, Shiming, Tong, Limin, Dai, Daoxin
• Format: Journal Article
• Language: English
• Published: England Springer Nature B.V 28.02.2020; Nature Publishing Group UK
• Subjects: Bandwidths; Graphene; Photonics; Silicon; Wavelength; Integrated optics; Silicon photonics; Optical properties and devices
• ISSN: 2047-7538; 2095-5545; 2047-7538
• DOI: 10.1038/s41377-020-0263-6

Graphene has attracted much attention for the realization of high-speed photodetection for silicon photonics over a wide wavelength range. However, the reported fast graphene photodetectors mainly operate in the 1.55 μm wavelength band. In this work, we propose and realize high-performance waveguide photodetectors based on bolometric/photoconductive effects by introducing an ultrathin wide silicon-graphene hybrid plasmonic waveguide, which enables efficient light absorption in graphene at 1.55 μm and beyond. When operating at 2 μm, the present photodetector has a responsivity of ~70 mA/W and a setup-limited 3 dB bandwidth of >20 GHz. When operating at 1.55 μm, the present photodetector also works very well with a broad 3 dB bandwidth of >40 GHz (setup-limited) and a high responsivity of ~0.4 A/W even with a low bias voltage of -0.3 V. This work paves the way for achieving high-responsivity and high-speed silicon-graphene waveguide photodetection in the near/mid-infrared ranges, which has applications in optical communications, nonlinear photonics, and on-chip sensing.