Perpendicularly Reversed Polarization Sensitivity of Double‐faced Photodetection based on Sb₂Se₃ Microbelt

Abstract Low‐dimensional polarization‐sensitive photodetectors have captured ever‐increasing attention due to their unique applications in navigation, optical switching, and communication. However, to date, the study of dimensionality‐dependent polarization‐sensitive photodetectors has not received much attention. Herein, a double‐faced polarization‐sensitive photodetector based on an individual high‐quality Sb₂Se₃ microbelt is proposed, where both the wide and narrow side facets serve as irradiation targets. Polarization‐sensitive measurements reveal the anisotropy in the photocurrents recorded parallel and perpendicular to the long axis of the Sb₂Se₃ microbelt. Strikingly, the single Sb₂Se₃ microbelt photodetector reveals the obvious perpendicular reversal with a 90° angle on polarization sensitivity from the wide surface to the narrow surface. With decreasing inclination angle, the anisotropic ratio varies from 1.18 to 0.87 gradually. Interestingly, the photodetector can lose its polarization sensitivity at a particular inclination angle. Angle‐resolved polarized Raman spectroscopy confirms the asymmetry and anisotropic character of the Sb₂Se₃ microbelt. The polarization sensitivity of the Sb₂Se₃ microbelt photodetectors originates from the optical anisotropy induced by the crystal structure anisotropy, rather than one‐dimensional geometry morphological anisotropy. The use of an anisotropic Sb₂Se₃ microbelt in double‐faced polarization‐sensitive photodetection may contribute to new functionality in innovative optoelectronic applications.