Tao He, Yukun Zhao, Xiaodong Zhang, Wenkui Lin, Kai Fu, Chi Sun, Fengfeng Shi, Xiaoyu Ding, Guohao Yu, Kai Zhang, Shulong Lu, Xinping Zhang, Baoshun Zhang
August 28, 2018
In this paper, a solar-blind ultraviolet photodetector (PD) based on the graphene/vertical Ga 2 O 3 nanowire array heterojunction was proposed and demonstrated. To the best of our knowledge, it is the first time that vertical Ga 2 O 3 nanowire arrays have been realized. Ga 2 O 3 nanowires were obtained by thermally oxidizing GaN nanowires grown by molecular beam epitaxy on n-doped Si substrate. Then, a monolayer graphene film was transferred to Ga 2 O 3 nanowires to form the graphene/vertical Ga 2 O 3 nanowire array heterojunction and transparent electrodes. The fabricated device exhibited a responsivity (R) of 0.185 A/W and rejection ratio (R258 nm/R365 nm) of 3×10 4 at the bias of −5 V. Moreover, the fast response times of this PD were 9 and 8 ms for the rise and decay times under 254 nm illumination, respectively, which are attributed to the unique properties of nanowire arrays and the graphene/vertical Ga 2 O 3 nanowire array heterojunction structure.