One-Dimensional Au鈥揨nO Heteronanostructures for Ultraviolet Light Detectors by a Two-Step Dielectrophoretic Assembly Method

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• 作者：Haitao Ding ; Jinyou Shao ; Yucheng Ding ; Weiyu Liu ; Hongmiao Tian ; Xiangming Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 17, 2015
• 年：2015
• 卷：7
• 期：23
• 页码：12713-12718
• 全文大小：360K
• ISSN：1944-8252

文摘

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鈥揨nO heterostructures cost efficiently is still in development. We report an efficient and well-controlled method to form Au鈥揨nO 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鈥揨nO heterostructures. After the adsorption of Au nanoparticles, the performances of Au鈥揨nO heteronanostructures in UV detection were studied. Experimental results indicate that the ratio of the photo-to-dark current of the Au鈥揨nO 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.