title: One-Dimensional Au-ZnO Heteronanostructures for Ultraviolet Light Detectors by a Two-Step Dielectrophoretic Assembly Method.
abstract: One-dimensional ZnO decorated with metal nanoparticles has received much attention in the field of ultraviolet light detection because of its high photosensitivity and fast response, while how to form effective metal-ZnO heterostructures cost efficiently is still in development. We report an efficient and well-controlled method to form Au-ZnO heterostructures by two-step dielectrophoretic assembly. First, ZnO nanowires dispersed in deionized water were assembled dielectrophoretically in a planar microelectrode system. To control the number and position of assembled ZnO nanowires, a planar triangle-shaped microelectrode pair was imposed with a high-frequency ac voltage signal in this assembly process. Then a droplet of Au nanoparticle suspension was applied to decorate the preformed ZnO nanowire by another dielectrophoretic assembly process. The near-field dielectrophoretic force induced by the existence of ZnO nanowire spanning the electrode gap attracts Au nanoparticles onto the surface of ZnO nanowires and forms effective Au-ZnO heterostructures. After the adsorption of Au nanoparticles, the performances of Au-ZnO heteronanostructures in UV detection were studied. Experimental results indicate that the ratio of the photo-to-dark current of the Au-ZnO heteronanostucture-based detector was improved significantly, and the photoresponse was accelerated considerably. This kind of enhancement in performance can be attributed to the localized Schottky junctions on the surface of ZnO nanowire which improves the surface band bending.
authors.affiliation: Micro- and Nano-manufacturing Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Ding
authors.affiliation: Micro- and Nano-manufacturing Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
authors.forename: Jinyou
authors.initials: J
authors.lastname: Shao
authors.affiliation: Micro- and Nano-manufacturing Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Micro- and Nano-manufacturing Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
authors.forename: Weiyu
authors.initials: W
authors.lastname: Liu
authors.affiliation: Micro- and Nano-manufacturing Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
authors.forename: Hongmiao
authors.initials: H
authors.lastname: Tian
authors.affiliation: Micro- and Nano-manufacturing Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
authors.forename: Xiangming
authors.initials: X
authors.lastname: Li
keywords: Au nanoparticle; ZnO nanowire; dielectrophoretic assembly; ultraviolet photodetector