ZnO/Ag纳米复合材料的制备及电学性能研究

The preparation of ZnO/Ag nanocomposites and study on electrical properties

在室温下,利用超声活化法将机械研磨13h的Zn粉在V(水)∶V(环己烷)=19∶1的分散体系中合成ZnO纳米颗粒悬浮液,然后通过光还原AgNO3制备出ZnO/Ag纳米复合材料。并用X射线粉末衍射仪(XRD)、透射电子显微镜(TEM)对ZnO/Ag复合颗粒表征,用扫描电子显微镜(SEM)和探针台I-V测试仪对ZnO/Ag复合薄膜表征和电学性能测试,通过XRD和TEM得出,超声合成的ZnO具有六方纤锌矿结构,长约20nm的短棒状;经光还原沉积在其表面的纳米Ag呈现面心立方结构,直径约为5nm。通过SEM和I-V伏安特性曲线得出,干燥温度对复合结构有较大影响,60℃干燥的复合薄膜比较致密均匀,导通电压大约2V左右,在100℃时开始转变为有氧化锌附着的枝状银网状复合物,导通电压在0.02V左右,通过控制干燥温度可改变复合薄膜中ZnO和Ag的结合方式以及相应的电学性能。

At room temperature,ZnO nanopartikel-suspension was prepared by ultrasonic method in the dispers-ed system of water and hexane （1 9∶1）with Zn which was processed by mechanical milling for 13 h.Then,Ag-NO 3 was photoredued to prepare ZnO/Ag nanocomposites.The XRD and TEM were use to analyze ZnO/Ag composite particles.The SEM and I-V tester were use to test ZnO/Ag composite thin films and electrical prop-erties.The results of XRD and TEM showed that ZnO synthesized by ultrasonic method was short rod-like with the wurzite hexagonal structure and length of about 20 nm;the structure of Ag nano-particles on the surface of ZnO by photo-reduction method was face-centered cubic.The SEM and I-V results revealed that drying temper-ature had a great influence on the composite structure.When drying temperature was 60 ℃,the composite thin film had compact and uniform structure and break-over voltage was about 2 V;when drying temperature was 100 ℃,the structure of the composite thin film was transformed into the Ag network of composites with ZnO branches and break-over voltage was about 0.02 V.By controlling the drying temperature,combinations of ZnO with Ag in composite thin films and the electrical properties could be changed.