Self-powered nn heterojunction UV imaging photodetectors based on <i>in-situ</i> -grown MAPbCl ₃ microplates on GaN substrates

Self-powered ultraviolet (UV) photodetectors are widely applicable in various fields due to their ability to operate autonomously, offering unparalleled portability and flexibility. In this letter, a high-performance self-powered UV photodetector based on MAPbCl₃/GaN nn heterojunction is demonstrated. The n-MAPbCl₃microplates were grown<i>in situ</i>on the n-GaN substrate using a simple solution process. Thanks to the differences in the energy band between MAPbCl₃and GaN, a built-in electric field is formed, which facilitates efficient separation of photo-generated charge carriers. This enables the photodetector to operate without the need of an external bias voltage. Furthermore, the wide bandgap of both MAPbCl₃and GaN endows the photodetector with exceptional sensitivity to UV light. The optimized MAPbCl₃/GaN device exhibits high-performance metrics, including low dark current and noise, high photo to dark current ratio, responsivity, and detectivity at zero bias.