Zhou Hao, Xu Shengqiang, Lin Yiding, Huang Yi-Chiau, Son Bongkwon, Chen Qimiao, Guo Xin, Lee Kwang Hong, Goh Simon Chun-Kiat, Gong Xiao, Tan Chuan Seng
Opt Express. 2020 Mar 30;28(7):10280-10293. doi: 10.1364/OE.389378.
We introduced photon-trapping microstructures into GeSn-based photodetectors for the first time, and achieved high-efficiency photo detection at 2 µm with a responsivity of 0.11 A/W. The demonstration was realized by a GeSn/Ge multiple-quantum-well (MQW) p-i-n photodiode on a GeOI architecture. Compared with the non-photon-trapping counterparts, the patterning and etching of photon-trapping microstructure can be processed in the same step with mesa structure at no additional cost. A four-fold enhancement of photo response was achieved at 2 µm. Although the incorporation of photo-trapping microstructure degrades the dark current density which increases from 31.5 to 45.2 mA/cm at -1 V, it benefits an improved 3-dB bandwidth of 2.7 GHz at bias voltage at -5 V. The optical performance of GeSn/Ge MQW photon-trapping photodetector manifests its great potential as a candidate for efficient 2 µm communication. Additionally, the underlying GeOI platform enables its feasibility of monolithic integration with other photonic components such as waveguide, modulator and (de)multiplexer for optoelectronic integrated circuits (OEICs) operating at 2 µm.
我们首次将光子捕获微结构引入基于GeSn的光电探测器中，并在2 µm波长处实现了高效光探测，响应度为0.11 A/W。该演示是通过在GeOI架构上的GeSn/Ge多量子阱（MQW）p-i-n光电二极管实现的。与无光子捕获的同类器件相比，光子捕获微结构的图案化和蚀刻可以与台面结构在同一步骤中进行，无需额外成本。在2 µm波长处实现了四倍的光响应增强。尽管引入光子捕获微结构会使暗电流密度降低，在-1 V时从31.5 mA/cm²增加到45.2 mA/cm²，但在-5 V偏置电压下，其3 dB带宽提高到了2.7 GHz。GeSn/Ge MQW光子捕获光电探测器的光学性能表明其作为2 µm高效通信候选器件具有巨大潜力。此外，底层的GeOI平台使其与其他光子组件（如波导、调制器和（解）复用器）进行单片集成成为可能，用于工作在2 µm的光电集成电路（OEIC）。
