▎ 摘　　要

GaN-based photodetectors are strongly desirable in many advanced fields, such as space communication, environ-mental monitoring, etc. However, the slow photo-response speed in currently reported high-sensitivity GaN-based photodetectors still hinders their applications. Here, we demonstrate a high-sensitivity and fast-speed UV photodetector based on asymmetric Au/ nanoporous-GaN/graphene vertical junctions. The nanoporous GaN-based vertical photodetector shows an excellent rectification ratio up to similar to 105 at +4 V/-4 V. The photo-responsivity and specific detectivity of the device is up to 1.01 x 104 A/W and 7.84 x 1014 Jones, respectively, more than three orders of magnitude higher than the control planar photodetector. With switching light on and off, the repeatable on/off current ratio of the nanoporous GaN-based vertical photodetector is similar to 4.32 x 103, which is about 1.51 x 103 times to that of the control planar device. The measured rise/ decay time is 12.2 mu s/14.6 mu s, which is the fastest value for the high-sensitivity GaN-based photodetectors to date. These results suggest that the asymmetric Au/nanoporous-GaN/graphene structure can improve the sensitivity and the photo-response speed of GaN-based PDs simultaneously.