Chao Xie, Xingtong Lu, Mengru Ma, Xiaowei Tong, Zhixiang Zhang, Li Wang, Chunyan Wu, Wenhua Yang, and Lin-Bao Luo*

Abstract:Photodetection in the solar-blind deep-ultraviolet (DUV) regime (200-280 nm) has received significant attention for its many critical applications in military and civil areas. In this study, a vapor-solid synthesis technique for catalyst-free growth of single-crystalline β-Ga₂O₃ nanowires has been developed. A photodetector made of the nanowires is highly sensitive to 265 nm DUV illumination with excellent photoresponse performance. The performance parameters including I_light/I_dark ratio, responsivity, specific detectivity and response speed can attain ~10³, ~233 AW^-1, ~8.16×10¹² Jones, and 0.48/0.04 s, respectively. Additionally, the detector has an abrupt response cutoff wavelength at ~290 nm with a reasonable DUV/visible (250 nm-to-405 nm) rejection ratio exceeding 10². It is also found that the device can operate properly at a large applied bias of 200 V with the responsivity being enhanced to as high as ~1680 AW^-1. Moreover, such a nanowires-based photodetector can function as a DUV light image sensor with a reasonable spatial resolution. Holding the above advantages, the present DUV photodetector based on catalyst-free grown β-Ga₂O₃ nanowires possesses huge possibility for application in future DUV optoelectronics.