Near-Infrared Polarization-Sensitive Detection by All-Si Plasmonic Hot Electron Detectors.

Tian, Shuoqiu; Yuan, Wentao; Yu, Yu; Guo, Jinyu; Liu, Kangping; Tong, Xujie; Chen, Qiucheng; Wu, Qingxin et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Polarization-sensitive optoelectronic detection has been achieved by an all-Si detector in the NIR range, based on plasmon hot electron generation/internal photoemission effect. An advanced architecture with a specially designed anisotropic metasurface was developed and structurally optimized for maximizing the internal quantum efficiency (IQE). Assisted by finite difference time domain (FDTD) simulations, the well-designed device exhibits a maximum optical absorption of 80% around 1.45 μm, corresponding to an optical discrimination ratio of 120. Optoelectronic measurements show the peak responsivity and detectivity of 51.2 mA/W and 8.05 × 10<sup>10</sup> cm Hz<sup>1/2</sup>/W, respectively, at 1.45 μm. A high polarization photocurrent ratio of 35 nm is also achieved at 1.55 μm. Moreover, the optoelectronic response can be tuned by a back-gate bias. Last but not least, we built up a model for theoretically estimating the IQE, which provides instructive guidance for further enhancing the optoelectronic performance of hot electron detectors.