Efficient Carrier Transport in 2D Bi2O2Se/CsBi3I10 Perovskite Heterojunction Enables Highly‐Sensitive Broadband Photodetection

Abstract

Abstract2D Bi2O2Se has recently garnered significant attention in the electronics and optoelectronics fields due to its remarkable photosensitivity, broad spectral absorption, and excellent long‐term environmental stability. However, the development of integrated Bi2O2Se photodetector with high performance and low‐power consumption is limited by material synthesis method and the inherent high carrier concentration of Bi2O2Se. Here, a type‐I heterojunction is presented, comprising 2D Bi2O2Se and lead‐free bismuth perovskite CsBi3I10, for fast response and broadband detection. Through effective charge transfer and strong coupling effect at the interfaces of Bi2O2Se and CsBi3I10, the response time is accelerated to 4.1 µs, and the detection range is expanded from ultraviolet to near‐infrared spectral regions (365–1500 nm). The as‐fabricated photodetector exhibits a responsivity of 48.63 AW−1 and a detectivity of 1.22×1012 Jones at 808 nm. Moreover, efficient modulation of the dominant photocurrent generation mechanism from photoconductive to photogating effect leads to sensitive response exceeding 103 AW−1 for heterojunction‐based photo field effect transistor (photo‐FETs). Utilizing the large‐scale growth of both Bi2O2Se and CsBi3I10, the as‐fabricated integrated photodetector array demonstrates outstanding homogeneity and stability of photo‐response performance. The proposed 2D Bi2O2Se/CsBi3I10 perovskite heterojunction holds promising prospects for the future‐generation photodetector arrays and integrated optoelectronic systems.