Wang Haibo, Zhang Jishen, Zhang Gong, Chen Yue, Huang Yi-Chiau, Gong Xiao
Opt Lett. 2021 May 1;46(9):2099-2102. doi: 10.1364/OL.419302.
We report on p-i-n waveguide photodetectors with a ${{\rm Ge}{0.92}}{{\rm Sn}{0.08}}/{\rm Ge}$ multiple-quantum-well (MQW) active layer on a strain-relaxed Ge-buffered silicon substrate. The waveguide-photodetector structure is used to elongate the photo-absorption path and keeps a short photo-generated carrier transmission path. In addition, the double-mesa structure with a low substrate doping concentration is implemented, which minimizes the parasitic capacitance. As a result, a high responsivity of 119 mA/W at ${-}{1};{\rm V}$ and a high bandwidth of more than 10 GHz at ${-}{7};{\rm V}$ were achieved at a 2 µm wavelength. Compared with the surface-illuminated photodetector, the responsivity was improved by ${\sim}{8}$ times at a 2 µm wavelength, while keeping the comparable bandwidth.
我们报道了一种基于应变弛豫锗缓冲硅衬底、具有${{\rm Ge}{0.92}}{{\rm Sn}{0.08}}/{\rm Ge}$多量子阱（MQW）有源层的p-i-n波导光电探测器。波导光电探测器结构用于延长光吸收路径，并保持较短的光生载流子传输路径。此外，采用了具有低衬底掺杂浓度的双台面结构，这使寄生电容最小化。结果，在2μm波长下，在-1V时实现了119mA/W的高响应度，在-7V时实现了超过10GHz的高带宽。与表面照明光电探测器相比，在2μm波长下响应度提高了约8倍，同时保持了相当的带宽。
