Fast and Sensitive Visible-Infrared Detection using Bi₂O₂Se/WS2 Heterostructure

Photodetectors play a vital role in optical imaging, communication, security monitoring, and environmental sensing. With the rapid advancement of artificial intelligence and autonomous driving, there is an increasing demand for devices exhibiting broadband absorption, high sensitivity, low power consumption, and fast response. However, the inherent limitations of their band structures restrict conventional thin-film photodetectors to narrow spectral ranges, resulting in suboptimal broadband performance. Herein, we showcase a broadband photodetector constructed from a Bi₂O₂Se/WS₂ van der Waals heterostructure. The built-in electric field arising from band alignment enables effective directional separation and transport of photogenerated electron-hole pairs, suppressing recombination, reducing dark current, and boosting photoelectric conversion efficiency. As a result, the device achieves broadband detection spanning 520-1550 nm at room temperature, featuring by a picoampere-level dark current, a high detectivity of 2.4×1012 Jones, and a fast response time of 27 μs. Our results offer a promising approach for multiband imaging applications and device miniaturization.