Visible–ultraviolet dual-band photodetectors based on an all-inorganic CsPbCl3/p-GaN heterostructure

Abstract

All-inorganic metal halide perovskites (MHPs) have attracted increasing attention because of their high thermal stability and band gap tunability. Among them, CsPbCl₃ is considered a promising semiconductor material for visible–ultraviolet dual-band photodetectors because of its excellent photoelectric properties and suitable band gap value. In this work, we fabricated a visible–ultraviolet dual-band photodetector based on a CsPbCl₃/p-GaN heterojunction using the spin coating method. The formation of the heterojunction enables the device to exhibit obvious dual-band response behavior at positive and negative bias voltages. At the same time, the dark current of the device can be as low as 2.42 × 10⁻⁹ A, and the corresponding detection rate can reach 5.82 × 10¹⁰ Jones. In addition, through simulation calculations, it was found that the heterojunction has a type II energy band arrangement, and the heterojunction response band light absorption is significantly enhanced. The type II energy band arrangement will separate electron–hole pairs more effectively, which will help improve device performance. The successful implementation of visible–ultraviolet dual-band photodetectors based on a CsPbCl₃/p-GaN heterojunction provides guidance for the application of all-inorganic MHPs in the field of multi-band photodetectors.