Inorganic CsBi3I10 perovskite/silicon heterojunctions for sensitive, self-driven and air-stable NIR photodetectors

Abstract

In this study, a sensitive near-infrared (NIR) photodetector based on a CsBi₃I₁₀ perovskite/Si heterojunction is developed by directly coating a layer of inorganic perovskite onto a 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, the critical photoresponse parameters of responsivity, external quantum efficiency and specific detectivity reached 178.7 mA W⁻¹, 27.2% and 4.99 × 10¹⁰ Jones at zero bias, respectively, which can be further increased to as high as 492.1 mA W⁻¹, 75.2% and 1.38 × 10¹¹ Jones 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 of storage under ambient conditions. Considering the good photoresponse performance and facile assembly approach, the CsBi₃I₁₀ perovskite/Si heterojunction possesses huge potential for future cost-effective and high-performance photodetection applications.