Low symmetric sub-wavelength array enhanced lensless polarization-sensitivity photodetector of germanium selenium

The structure of sub-wavelength array (SWA) oriented along the low-symmetric atomic direction could enhance the polarization ratio (PR) of in-plane anisotropic 2D materials. By applying the SWA strategy to the stable anisotropic 2D GeSe, the PR increases from 1.6 (pristine GeSe flake) to 18 (GeSe SWA) with the array width of 200 nm and proportion of 25%. For the SWA strategy, it shows the ability of PR enhancement in full detection wavelength especially in the wavelength corresponding to the band gap.