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

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 (Bi 2 O 2 Se) is gradually showing great research significance in the optoelectronic field. Here, we develop a bismuth oxyselenide/p-silicon (Bi 2 O 2 Se/p-Si) heterojunction and design a self-powered and broadband Bi 2 O 2 Se/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 × 10 12 cm Hz 1/2 W -1 and a self-powered photoresponse characteristic at 365-1550 nm (ultraviolet-near-infrared). Meanwhile, the Bi 2 O 2 Se/p-Si heterojunction photodetector also shows high stability and repeatability. It is expected that the proposed Bi 2 O 2 Se/p-Si heterojunction photodetector will expand the applications of Bi 2 O 2 Se in practical integrated circuits in the field of material science, energy development, optical imaging, biomedicine, and other applications.