A sub-wavelength plasmonic Au–Ge grating was used to enhance the responsivity of Ge-based metal–semiconductor–metal photodetectors at infrared communication wavelengths. Furthermore, a finite-difference time-domain simulation was performed to optimize absorption of light by the detectors. Characterizations of the photoelectronic properties of the optimized device revealed high-performance photodetection with a responsivity of 0.38 A/W and an external quantum efficiency of 30% for 1.55 μm wavelength incident light. Moreover, an enhancement peak across three infrared telecommunication bands (C-band, L-band, and U-band) was achieved in the plasmon-enhanced photodetector. According to the simulation results of the optical absorption spectra, the distributions of electric field, and absorbed power, the enhancements of responsivity and quantum efficiency could be ascribed to the surface plasmons at the Au/Ge interface. These plasmons boosted inter-band transition and internal photoemission effect simultaneously, enabling high efficient photodetection around the C-band. The results of the fabricated devices demonstrated the potential of this approach for achieving high-performance Ge-based photodetectors.

中文翻译：

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通过双重吸收机制增强的高性能红外锗基等离激元光电探测器

亚波长等离子Au-Ge光栅用于增强基于Ge的金属-半导体-金属光电探测器在红外通信波长下的响应度。此外，进行了有限差分时域仿真，以优化检测器对光的吸收。优化的装置的光电特性的表征揭示了高性能光检测用0.38 A / W的响应和30％的1.55的外部量子效率μ米波长的入射光。此外，在等离激元增强型光电探测器中，在三个红外电信频段（C频段，L频段和U频段）上实现了增强峰。根据光吸收光谱，电场分布和吸收功率的模拟结果，可以将响应度和量子效率的提高归因于Au / Ge界面处的表面等离子体。这些等离子体激元同时增强了带间跃迁和内部光发射效应，从而实现了C波段附近的高效光电检测。所制造器件的结果证明了这种方法在实现高性能基于Ge的光电探测器方面的潜力。