High-Performance Zero-Powered InHfO/GaN Photodetectors for Ultraviolet Image Sensing Systems

Abstract

The advancement of photodetector technology, particularly in enhancing response speed and photosensitivity, is crucial for the development of high-density optical arrays and image sensing systems. Wide-bandgap indium oxide with high electron mobility is ideal for fabricating ultraviolet photodetectors capable of high-speed response. Nonetheless, photodetectors based on single indium oxide semiconductors exhibit a large dark current and high energy consumption, which hinders their practical application in photodetection. In this research, we fabricated an indium–hafnium oxide/gallium nitride (IHO/GaN) ultraviolet photodetector via atomic layer deposition. This method not only reduces the photodetector’s response time but also allows it to realize optoelectronic conversion without external power. Simultaneously, the optimized photodetector exhibits remarkable performance metrics under 280 nm ultraviolet illumination, including a responsivity of 375 mA/W, a detectivity of 4.4 × 10¹² Jones, a photo-dark current ratio of 3.3 × 10⁵ %, and a rise/fall time of 42/66 ms. The exceptional performance is credited to the swift separation of photogenerated electron–hole pairs, facilitated by the substantial built-in electric field present in the depletion region at the p–n junction interface. Additionally, arrayed IHO/GaN photodetectors demonstrate potential to apply in image recognition systems, providing an effective strategy for constructing high-performance zero-powered ultraviolet detectors for optical imaging.