A high-performance broadband polarization-sensitive photodetector based on BiSeS nanowires

Bismuth selenide (Bi₂Se₃) has emerged as a promising material for high-performance photodetectors due to its wideband spectral response, strong in-plane anisotropy, narrow bandgap, high absorption coefficient, and carrier mobility. However, inherent defects and states in Bi₂Se₃-based devices reduce optical conversion efficiency and stability. To address these challenges, we report the design and preparation of Bi₂Se_2.33S_0.67 nanowires by a facile chemical vapor transport method. The individual Bi₂Se_2.33S_0.67 nanowire photodetectors exhibit remarkable photoresponse over a broadband wavelength region ranging from ultraviolet C (254 nm) to near-infrared (1064 nm) with a low dark current of 0.015 nA and the measured maximum photoresponsivity of 2.52 A W^-1 at 532 nm, together with a detectivity of around 5.2 × 10¹¹ Jones. Furthermore, the photoresponse of photodetectors exhibits polarization angle sensitivity within a broadband range of 355 to 808 nm. The structural anisotropy of the Bi₂Se_2.33S_0.67 crystal leads to a maximum dichroic ratio of about 1.8 at 355 nm. Additionally, cat images produced by this device further demonstrate the potential of the high-performance devices, and the effectiveness of photodetectors in deep learning image recognition validates their wide-spectrum, high-responsivity, and superior polarization-sensitive detection capabilities.