Vacuum Ultraviolet (120–200 nm) Avalanche Photodetectors

Abstract Ultra‐sensitive photodetectors that can operate at vacuum ultraviolet (VUV) wavelengths are greatly needed in space exploration as well as photolithography sensing and imaging. Traditional photomultiplier tubes for weak VUV light detection have the characteristics of large physical volume and high working voltage, and thus, the development of ultra‐wide‐bandgap semiconductor‐based avalanche photodetectors (APD) with advantages of miniaturization, radiation resistance, and filter‐free characteristics is urgently needed. Here, this work reports the details and results of APDs prepared for VUV detection based on high‐quality AlN heterojunctions. An extremely low dark current of ≈30 fA is achieved, and appreciable spectral response in the range of 120–220 nm and a gain >4000 at room temperature are demonstrated for the first time. Such APDs with integrability are attractive for single‐photon detection and imaging at VUV wavelengths in the future.