Enhanced optoelectronic performances of FePS3/ReS2 Van der Waals heterostructures with type-II band alignment

Abstract

FePS3, as a typical represent of newly emerged transition metal chalcogenophosphates (TMCPs) with antiferromagnetic properties, has been considered as a splendid candidate for ultraviolet (UV) photodetectors. However, the limited response spectra band and photoresponsivity has seriously restricted its applications. As a typical representative of transition metal Re-based chalcogenides, ReS2 has an adjustable absorption band gap in the visible light band and extremely weak interlayer coupling force, which makes the material have higher absorbance and exciton transition probability, thereby greatly enhancing PL. Herein, we construct a high performance photodetector based on FePS3/ReS2 van der Waals (vdWs) heterostructure with excellent optical and optoelectronic properties. The in-plane optical anisotropic ratio of ReS2 nanoflake is significantly enhanced owing to the strong vdWs interlayer couplings, which is confirmed by the linear-polarized photoluminescence (PL) spectra. The photodetector exhibits broadband response spectrum ranging from UV to near-infrared (NIR) region, high photoresponsivity upto 102.5 A/W at 305 nm and 41.8 A/W at 638 nm, and fast response speed with rising/decaying times about 0.22/1.22 ms, which displays excellent superiority over other FePS3-based photodetectors. The high performances of FePS3/ReS2 are primarily attributed to the high electron mobility, strong light-matter interactions and built-in electric field at the heterointerface with type-II band alignment. The eminent and novel optoelectronic properties of the heterostructure pave promising platforms for the further development and applications of TMCPs in high-performance photodetections.