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
1State Key Laboratory for Modern Optical Instrumentation, Zhejiang Provincial Key Laboratory for Sensing Technologies, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Zijingang Campus, 310058 Hangzhou, China.
2Ningbo Research Institute, Zhejiang University, 315100 Ningbo, China.
Light Sci Appl. 2020 Feb 28;9:29. doi: 10.1038/s41377-020-0263-6. eCollection 2020.
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.
石墨烯因能在宽波长范围内实现硅光子学的高速光电探测而备受关注。然而，已报道的快速石墨烯光电探测器主要工作在1.55μm波长波段。在这项工作中，我们通过引入超薄宽硅-石墨烯混合等离子体波导，基于测辐射热/光电导效应提出并实现了高性能波导光电探测器，该波导能使石墨烯在1.55μm及更长波长处实现高效光吸收。当工作在2μm波长时，当前的光电探测器响应度约为70mA/W，设置限制的3dB带宽大于20GHz。当工作在1.55μm波长时，当前的光电探测器同样表现出色，具有大于40GHz（设置限制）的宽3dB带宽以及即使在-0.3V的低偏置电压下仍约为0.4A/W的高响应度。这项工作为在近/中红外范围内实现高响应度和高速硅-石墨烯波导光电探测铺平了道路，其在光通信、非线性光子学和片上传感等领域具有应用价值。
