Xiao-Wei Tong, Zhi-Xiang Zhang, Di Wang, Lin-Bao Luo,* Chao Xie,* Yu-Cheng Wu,*

Abstract:In this study, a sensitive near-infrared (NIR) photodetector based on CsBi₃I₁₀perovskite/Si heterojunction is developed by directly coating a layer of inorganic perovskite onto planar Si substrate. The as-constructed heterojunction displays a representative current rectifying behavior in the dark and remarkable photoresponse properties upon light irradiation. The distinct photovoltaic effect enables the device to function as a self-driven photodetector working at zero bias. Furthermore, it is observed that the photodetector is sensitive in a wide spectral region with peak sensitivity at ~820 nm. Under 808 nm illumination, some critical photoresponse parameters including responsivity, external quantum efficiency and specific detectivity attain 178.7 mAW^-1, 27.2% and 4.99´10¹⁰ Jones at zero bias, respectively, which can be further increased to be as high as 492.1 mAW^-1, 75.2% and 1.38´10¹¹ Jones when working at a working bias of -1 V. What is more, the present device also holds a large I_light/I_dark ratio of ~1´10₄, a rapid response speed of 73/36 μs, and excellent air stability even after 3 months storage in ambient conditions. Considering the good photoresponse performance and facile assembly approach, the CsBi₃I₁₀ perovskite/Si heterojunction possesses huge possibility for future cost-effective and high-performance photodetection application.