Abstract: Flexible ultraviolet photodetectors are widely investigated for applications in wearable electronics and environmental monitoring due to their lightweight characteristics and compatibility with complex surfaces. Amorphous gallium oxide (a-Ga₂O₃), with its wide bandgap of 4.9 eV, is highly suitable for flexible solar-blind UV detection. However, deep-level defects such as oxygen vacancies have long degraded the performance of a-Ga₂O₃-based flexible detectors. In addition, achieving large-area flexible devices remains challenging, which continues to constrain their development. Herein, an oxygen-rich design strategy is employed to shorten the device response time to 4.3/11.2 ms, suppress the dark current from 6.9 to 0.3 µA, and enhance the detector bandwidth up to 600 dB. The 4-inch wafer-scale flexible a-Ga₂O₃ detectors are realized by leveraging mechanical thinning and wet etching processes. Remarkably, the devices exhibited highly consistent performance before and after transfer, as well as under repeated bending at various angles and temperature variations. Furthermore, a large-area flexible detector array comprising 144 pixels is fabricated, and high-contrast ultraviolet imaging is successfully demonstrated. This study provides a significant reference for the development of high-performance, wafer-scale a-Ga₂O₃-based flexible detectors.

Key words: Ga₂O₃, Photodetector, Flexible devices, Wafer-scale, Oxygen vacancy