Controllable Vapor Growth of 2D Layered SbI ₃ Nanosheets for High‐Performance Visible‐Light Photodetectors

Abstract 2D semiconductors have a wide range of applications in electronics and optoelectronics because of their unique structure and properties. As an emerging 2D metal‐halide, SbI ₃ provides an ideal platform for fundamental physical studies and optoelectronic device exploration. Here, controllable growth of high‐quality SbI ₃ nanosheets are achieved with thickness ranging from 60 to 550 nm and lateral size of 20 to 170 µm by vapor phase deposition. Detailed structural characterizations reveal that the growth of SbI ₃ nanosheets on mica substrate is incommensurate hetero‐epitaxy with the epitaxial relationship of (110)SbI ₃ //(110)mica and (300)SbI ₃ //(200)mica. The UV–vis light absorption spectrum indicates that SbI ₃ is an indirect bandgap semiconductor with a bandgap of 2.15 eV. Temperature‐dependent PL reveals anomalous peak energy shifts, attributed to interplay between electron‐phonon coupling and thermal expansion. The photodetectors (PDs) fabricated with the SbI ₃ nanosheets can work in the spectral range of 350–575 nm. Under the illumination of 405 nm laser, the PDs possess a responsivity of 1.55 A W ⁻¹ , detectivity of 8.4 × 10 ¹⁰ Jones, which are comparable to PDs of other 2D metal halides. Furthermore, the PDs of SbI ₃ sheets exhibit potential in imaging applications. This work paves the way to the controllable growth of SbI ₃ nanosheets for high‐performance visible‐light photodetection.