Strong In-Plane Anisotropic SiP2 as a IV–V 2D Semiconductor for Polarized Photodetection

In-plane anisotropic two-dimensional (2D) materials, emerging as an intriguing type of 2D family, provide an ideal platform for designing and fabrication of optoelectronic devices. Exploring air-stable and strong in-plane anisotropic 2D materials is still challenging and promising for polarized photodetection. Herein, SiP 2, a 2D IV–V semiconductor, is successfully prepared and introduced into an in-plane anisotropic 2D family. The basic characterizations combined with theoretical calculations reveal 2D SiP 2 to exhibit an intrinsically low-symmetry structure, the in-plane anisotropy of phonon vibrations, and an anisotropically dispersed band structure. Moreover, the photodetector based on 2D SiP 2 exhibits high performance with a high detectivity of 10 12 Jones, a large light on/off ratio of 10 3, a low dark current of 10 –13 A, and a fast response speed of 3 ms. Furthermore, 2D SiP 2 demonstrates a high anisotropic photodetection with an anisotropic ratio up to 2. In addition, the polarization-sensitive photodetector presents a dichroic ratio of 1.6 due to the intrinsic linear dichroism. These good characteristics make 2D SiP 2 a promising candidate as an in-plane anisotropic semiconductor for high-sensitivity and polarized optoelectronic applications.