Vertically aligned ZnO/Ga2O3 core/shell nanowire arrays as self-driven superior sensitivity solar-blind photodetectors

With a large interfacial area, better light absorption ability and well-controlled morphology, vertically arrayed one-dimensional core/shell nanostructures are considered as ideal candidate geometries for high-performance photodetectors. Herein, vertically aligned ZnO nanowire arrays were fabricated by the vapor phase transport approach and then homogeneously coated with 20 nm thick monoclinic Ga2O3 through sputtering methods, and can be used as self-driven solar-blind photodetectors. These devices exhibit excellent photosensitive characteristics with a large I-light/I-dark ratio of 2.64 x 10(4), an ideal detectivity of 6.11 x 10(12) cm Hz(1/2) W-1, and a superior responsivity of 137.9 mA W-1 under 254 nm light without an exterior power supply, which are much higher than those of other previously reported self-powered Ga2O3-based photodetectors. What is more, an ultrafast response speed (rise time approximate to 28.9 s and fall time approximate to 85.7 s) is observed in the photodetectors by the time-resolved photoresponse test. Such excellent performances are assigned to the unique core-shell nanoarchitecture and built-in electric field at ZnO and Ga2O3 junction interfaces can rapidly separate photogenerated carriers. Our work provides a facile yet efficient fabrication procedure to construct self-powered core/shell nanowire arrays as solar-blind photodetectors for huge application potential in future optoelectronic devices.