A Self‐Powered High‐Performance UV Photodetector Based on Core–Shell GaN/MoO 3– x Nanorod Array Heterojunction

Abstract Self‐powered UV photodetectors are highly desirable for applications in space communications and environmental monitoring. However, most self‐powered UV photodetectors exhibit unimpressive performance in weak signal detection. Herein, a self‐powered UV photodetector based on the core–shell GaN/MoO 3– x nanorod array (NRA) heterojunction system is demonstrated. Homogeneous MoO 3– x layers are deposited on GaN NRAs by a simple one‐step physical vapor deposition method. The photodetector device shows an ultrahigh specific detectivity of 2.7 × 10 15 Jones at 355 nm without any power supply. Further analyses reveal a responsivity of 160 A W −1 and a high UV–vis rejection ratio ( R 355 nm / R 400 nm ) of 2.0 × 10 4 under zero bias. The self‐powered device also has a fast response speed with a rise/fall time of 73/90 µs. As a result, the self‐powered photodetector, featuring ultrahigh detectivity and responsivity along with fast response, exhibits great potential for applications in next‐generation UV detection. The core–shell NRA structure heterojunction design provides a valuable direction for realizing nanoscale self‐powered UV photodetectors.