Ultrahigh-Responsivity GaON Thin Film Transistor Photodetectors with Improved Air Stability

As an ultrawide-bandgap semiconductor, gallium oxide (Ga₂O₃) exhibits intrinsic absorption characteristics in the solar-blind ultraviolet (SBUV) spectrum, holding immense potential for SBUV detection applications. However, achieving amorphous Ga₂O₃ photodetectors with simultaneously high responsivity and air stability remains a critical challenge. In this work, a strategy combining N-doping and low-temperature crystallization enhances both responsivity and air stability. An aluminum oxide (Al₂O₃) capping layer is introduced, which further acts as an effective optical modulation layer, enhancing the selectivity in the SBUV spectrum. Notably, compared to the control group, devices with an Al₂O₃ capping layer exhibited nanocrystalline structures in both the Al₂O₃ and channel layers, demonstrating superior performance, particularly an exceptional responsivity of 7.8 × 10⁵ A/W. The performance remains stable after being exposed to air for 100 days. These findings underscore the importance of microstructural engineering in oxide photodetector development, providing a concise and efficient technical pathway for advancing high-performance photodetectors and their industrial applications.