Self-powered polarization-sensitive photodetection and imaging based on Sb2Se3 microbelt/Si van der Waals heterojunction with MXene transmittance window

Polarization-sensitive detection and imaging have many significant applications in target recognition, optical switches, industrial inspection, and so on. Herein, on-chip near-infrared photodetectors based on individual Sb2Se3 microbelt/Si van der Waals heterojunction with MXene transmittance window were designed. The fabricated Sb2Se3 microbelt/Si photodetector displays a broad spectral response that spans the visible to near-infrared light regions, as well as a peak photoresponse at a wavelength of 1000 nm. The optimized Sb2Se3 microbelt/Si photodetector exhibits excellent photovoltaic performance with an ultralow dark current of 10 pA, a high responsivity of 25 mA/W, a favorable detectivity of 1010 Jones, a fast response time of 1.7 ms/2.9 ms under near-infrared illumination with power density of 0.1 mW/cm2. The identified performance can be attributed to the heterojunction's type-II band configuration, making it suited for the quick separation of photo-generated carriers. More importantly, polarization-sensitive photodetectors with an anisotropy ratio of 1.21 to 1.28 under the illumination of 940 nm light can be achieved. The Sb2Se3 microbelt/Si photodetector also demonstrates high-resolution single-pixel polarimetric imaging at zero bias. This work demonstrates an effective strategy for using anisotropic/isotropic Sb2Se3 microbelt/Si van der Waals heterojunction to realize high-performance, self-powered, and polarization-sensitive detection and imaging.