Low‐Symmetry and Nontoxic 2D SiP with Strong Polarization‐Sensitivity and Fast Photodetection

Abstract The in‐plane anisotropic feature of 2D layered materials has captured enormous research interest due to their application in polarization‐sensitive photodetection. Here, silicon phosphide (SiP), as a novel member of group IV–V 2D materials, is first introduced to the anisotropic 2D materials family with a high in‐plane anisotropy. The low‐symmetry structure, optical and optoelectronic properties are investigated systematically. Impressively, the photodetectors based on 2D SiP demonstrate high performance with low dark current, a fast response speed of 30 µs, and a strong anisotropic photoresponse with an anisotropic factor of 2.9. Furthermore, a strong polarization‐sensitive photodetector with a dichroic ratio up to 2.3 is realized based on the intrinsic linear dichroism of 2D SiP. This work not only provides an insight into the in‐plane anisotropic properties of 2D SiP, but also sheds light on its great potentials in anisotropic optoelectronic applications.