Near-Infrared\nPolarization-Sensitive Detection by\nAll-Si Plasmonic Hot Electron Detectors

Polarization-sensitive optoelectronic detection has been\nachieved\nby an all-Si detector in the NIR range, based on plasmon hot electron\ngeneration/internal photoemission effect. An advanced architecture\nwith a specially designed anisotropic metasurface was developed and\nstructurally optimized for maximizing the internal quantum efficiency\n(IQE). Assisted by finite difference time domain (FDTD) simulations,\nthe well-designed device exhibits a maximum optical absorption of\n80% around 1.45 μm, corresponding to an optical discrimination\nratio of 120. Optoelectronic measurements show the peak responsivity\nand 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\nphotocurrent ratio of 35 nm is also achieved at 1.55 μm. Moreover,\nthe optoelectronic response can be tuned by a back-gate bias. Last\nbut not least, we built up a model for theoretically estimating the\nIQE, which provides instructive guidance for further enhancing the\noptoelectronic performance of hot electron detectors.