| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 106 === Graphene shows remarkable optical and electronic properties that attract enormous interest. Graphene was first exfoliated mechanically from graphite in 2004. Chemical vapor deposition (CVD) is a method which can produce high quality graphene film. However, the separation of graphene film grown on metallic catalyst by CVD usually uses the chemical etching method to dissolve the metallic catalyst which causes environmental pollution in large-scale fabrication. Thus, in this study, reduced graphene oxide (RGO) film was fabricated by photocatalystic reduction of graphene oxide on ZnO nanowire array grown by hydrothermal method. The structure and chemical changes of nanosturctures were analyzed by SEM, ESCA, FTIR, and Raman spectroscopy. The photosensing properties of RGO films were also investigated.
The results show that the growth rate of RGO films was increased with increasing light intensity, and the thickness of film was increased by increasing reaction time.
The graphene oxide suspension pretreated by ZnO nanowire array-photocatalystic reduction can increase the growth rate of RGO films because that the graphene oxide in the suspension was partial reduction after pretreatment process. The adsorbing clusters on the RGO film were reduced using this pretreatment suspension standing for 24 hours. The reduction mechanism is breaking C-OH bonds and forming C-H bonds.
The RGO films have fast response in the visible and near-infrared sensing. For 660 nm visible light sensing, the response sensitivity was 103.1% at the applied voltage of 1V and the light intensity of 123.7 mW/cm2. A linear relationship exists between light intensity and photocurrent. For 940 nm near-infrared light sensing, the response sensitivity was 88.0% at the applied voltage of 1V and the light intensity of 16.0 mW/cm2. The slope of photocurrent vs light intensity curve was decrease with increasing of light intensity.
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