Broadband Mid‐Infrared Polarization‐Sensitive Photodetection Based on BP/Ta₂NiS₅ Heterojunction

Abstract The burgeoning demand for future integrated sensing and imaging devices have spurred the successful development of on‐chip polarization‐sensitive photodetectors. Although 2D materials with inherent anisotropic properties exhibit remarkable potential in on‐chip devices, their polarization sensitivity and photoelectric response remain constrained by intrinsic dichroism. The pressing need for high‐performance and multifunctional mid‐infrared (MIR) photodetectors persists as a formidable challenge. In this study, a BP/Ta₂NiS₅ heterojunction is constructed to achieve multifunctional photodetection. This device demonstrates the broadband and polarization‐sensitive photodetection, leveraging the inherent characteristics of heterostructures. Notably, the photodetector achieves a zero‐bias high polarization ratio (PR) of 17.8 and a responsivity of 25.4 mA W⁻¹ at 3.7 µm. Additionally, the high polarization sensitivity across 3.7 to 6.1 µm endows this device with practical usage, realizing polarization imaging and code communication. These findings lay the groundwork for the future development of multifunctional on‐chip polarization‐sensitive optoelectronic devices.