Self-Powered and Broadband Bismuth Oxyselenide/p-Silicon Heterojunction Photodetectors with Low Dark Current and Fast...

Inorganic nanomaterials such as graphene, black phosphorus, and transition metal dichalcogenides have attracted great interest in developing optoelectronic devices due to their efficient conversion between light and electric signals. However, the zero band gap nature, the unstable chemical properties, and the low electron mobility constrained their wide applications. Bismuth oxyselenide (Bi₂O₂Se) is gradually showing great research significance in the optoelectronic field. Here, we develop a bismuth oxyselenide/p-silicon (Bi₂O₂Se/p-Si) heterojunction and design a self-powered and broadband Bi₂O₂Se/p-Si heterojunction photodetector with an ultrafast response (2.6 μs) and low dark current (10^-10 A without gate voltage regulation). It possesses a remarkable detectivity of 4.43 × 10¹² cm Hz^1/2 W^-1 and a self-powered photoresponse characteristic at 365-1550 nm (ultraviolet-near-infrared). Meanwhile, the Bi₂O₂Se/p-Si heterojunction photodetector also shows high stability and repeatability. It is expected that the proposed Bi₂O₂Se/p-Si heterojunction photodetector will expand the applications of Bi₂O₂Se in practical integrated circuits in the field of material science, energy development, optical imaging, biomedicine, and other applications.