High-Performance and Stable Sb₂S₃ Thin-Film Photodetectors for Potential Application in Visible Light Communication

Photodetectors (PDs) are critical parts of visible light communication (VLC) systems for achieving efficient photoelectronic conversion and high-fidelity transmission of signals. Antimony sulfide (Sb 2 S 3 ) as a nontoxic, high optical absorption coefficient, and low-cost semiconductor becomes a promising candidate for applications in VLC systems. Particularly, Sb 2 S 3 PDs were verified to have significantly weak light detection ability in the visible region. However, the response speed of Sb 2 S 3 PDs with existing device structures is still relatively slow. Herein, through optimizing the device structure for the p–i–n type PDs, a p-type Sb 2 Se 3 hole transport layer (HTL) is designed to enhance the built-in electric field and to accelerate the migration of photogenerated carriers for the high responsivity and fast response speed. The optimal thickness of the structure is obtained through the simulation of SCAPS-1D software, and the optimized devices show high-performance parameters, including a responsivity of 0.34 A W –1, a specific detectivity ( D * ) of 2.20 × 10 12 Jones, the −3 dB bandwidth of 440 kHz, high stability, and the value of the Sb 2 S 3 PDs can reach 60% in the range of 360–600 nm, which indicates that the device is very suitable for working in the visible light band. In addition, the resulting Sb 2 S 3 PD is successfully integrated into VLC systems by designing a matched light detection circuit. The results suggest that the Sb 2 S 3 PDs are expected to provide an alternative to future VLC system applications.