2D Growth of BiSCl as Anisotropic Photodetector with Ultrahigh Responsivity and Detectivity

Abstract BiSCl, which shares the anisotropic chain‐like lattice configuration with the Bi^VX^VIY^VII (XS, Se; YCl, Br, I) family displays high photoelectric conversion efficiency in the UV–vis wavelength region. The current difficulty in 2D growth restricts the investigation of device performance and further integration. Herein, an epitaxial growth strategy for 2D BiSCl is proposed based on the principle of sharing a chloridion layer at the BiSCl/BiOCl interface. The interfacial atomic arrangement is carefully revealed using atomic resolved AC‐TEM(Spherical Aberration High Transmission Electron Microscope) and demonstrated by calculations based on density functional theory. Benefiting from its compatibility with PS‐assisted large‐scale transfer technology, the photoelectric performance is evaluated by constructing a standard symmetrical photoconductor and Graphene‐BiSCl Schottky junction device. High responsivity (1.71 × 10⁴ A W⁻¹) and detectivity (5.9 × 10^16. Jones) are achieved at 405 nm, and robustness is shown in a broadband spectrum, which manifested prominent anisotropic photoelectric behavior and great potential in weak‐light detection. These results elucidate the photoelectric applications of BiSCl semiconductors and the structural design of the Bi^VX^VIY^VII family.