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/cm² 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.

中文翻译：

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高效GeSn / Ge多量子阱光电探测器，其光子捕获微结构的工作频率为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，并以0.11 A / W的响应度实现了2 µm的高效光电探测。该演示是通过GeOI架构上的GeSn / Ge多量子阱（MQW）引脚光电二极管实现的。与非光子俘获对应物相比，光子俘获微结构的图案化和蚀刻可以在具有台面结构的同一步骤中进行，而无需额外费用。在2 µm处实现了4倍的光响应增强。尽管引入了光捕获微结构，但降低了暗电流密度，该暗电流密度从31.5 mA / cm ²增加到45.2 mA / cm ²在-1 V时，在-5 V的偏置电压下，它可改善2.7 GHz的3-dB带宽。GeSn/ Ge MQW俘获光子光电探测器的光学性能显示出其巨大潜力，可作为有效2 µm通信的候选者。此外，底层的GeOI平台使其能够与其他光子组件进行单片集成，例如工作在2 µm的光电集成电路（OEIC）的波导，调制器和（解）多路复用器。