Visible-Light Self-Powered Photodetector with High Sensitivity Based on the Type-II Heterostructure of CdPSe/MoS.

Transition metal thiophosphates (MTPs) are a group of emerging van der Waals materials with widely tunable band gaps. In the MTP family, CdPSe is demonstrated to possess a wide energy band gap and high carrier mobility, making it a potential candidate in optoelectronic applications. Here, we reported photoelectric response behaviors of both CdPSe- and CdPSe/MoS-based photodetectors (noted as CPS and CM, respectively); these showed prominent photoelectric performances, and the latter proved to be significantly superior to the former. These devices exhibited ultralow dark current at a magnitude order of 10 A and fine cycle and air stabilities. Compared with CPS, CM demonstrated the highest responsivity (91.12 mA/W) and detectivity (1.74 × 10 Jones) at 5 V under 425 nm light illumination. Besides, CM showed self-powered photoelectric responses at zero bias, which was attributed to the improved separation efficiency of photogenerated carriers by the built-in electric field at the interface of the p-n junction. This work proves a prospect for the CM device in portable, self-powered optoelectronic device applications.