静电力显微镜研究二相材料及其界面介电特性

摘要

利用静电力显微镜(EFM)研究了二相材料不同区域的介电特性。制备了高定向石墨/聚乙烯、云母/聚乙烯等层叠状二相材料复合物，在EFM相位检测模式下观测二相材料过渡界面处，可以发现二相材料中介电常数较大的材料会引起较大的相位滞后角∆θ该相位滞后角正切值tan(∆θ)与探针电压VEFM存在二次函数关系，且函数二次项系数与样品的介电常数存在增函数关系，进而可在微纳米尺度下区分不同微区域内材料的介电常数差异。研究表明EFM可用于对材料介电特性的微纳米尺度测量，这对分析复合材料二相界面区域特性有积极意义。%Dielectric property of two-phase stack-up sample is studied by electric force microscopy (EFM). Highly oriented pyrolytic graphite (HOPG)/polyethylene(PE) and mica/PE are fabricated. The phenomenon that phase shift (∆θ) of conducting probe varys with dielectric constant of material is discovered near the interface between the two materials by using phase detection EFM. The characteristic curves of tan(∆θ) versus tip voltage VEFM are of parabolic type. Quadratic coefficient increases with dielectric constantε increasing. An approach to the qualitative analysis of the dielectric property near the interface between different material at the micro/nanometer scale, is provided in this paper.