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通过旋涂法,采用Zn(OAc)2·2H2O和聚环氧乙烷(PEO)的水溶液为前驱体在不同的热处理温度下制备了ZnO薄膜.PEO的加入增加了溶液的成膜性,其较低的热分解温度有利于制得纯净的ZnO薄膜.文中考察了在不同热处理温度下制备的ZnO薄膜的形貌、结晶性、带隙(Eg)以及电导性.原子力显微镜(AFM)测试表明在热处理温度为400、450和500℃制备的ZnO薄膜的粗糙度均方根值分别为3.3、2.7和3.6nm.采用透射电子显微镜(TEM)测试发现ZnO薄膜中含有大量纳晶粒子.通过测试ZnO薄膜的UV-Vis吸收光谱,根据薄膜位于373nm处的吸收带边计算得到ZnO的带隙为3.3eV.通过对薄膜的电流-电压(I-V)曲线的测试计算得到在热处理温度为400、450和500℃制备的ZnO薄膜的电阻率分别为3.3×109、2.7×109和6.6×109Ω·cm.450℃时制备的ZnO薄膜的电阻率最小,主要是由于较高的热处理温度有利于提高薄膜的纯度、密度和吸附氧.而纯度较高、密度较大的薄膜电阻率比较小;吸附氧含量增加,晶界势垒增大,电阻率增大.因此在纯度和吸附氧的双重作用下450℃时制备的ZnO薄膜的电阻率最小,而500℃时制备的ZnO薄膜的电阻率最大.
ZnO thin films were prepared by spin coating and aqueous solutions of Zn (OAc) 2 · 2H2O and polyethylene oxide (PEO) as precursors at different heat treatment temperatures.The addition of PEO increased the film-forming ability of the solution The lower thermal decomposition temperature is conducive to the preparation of pure ZnO thin films.In this paper, the morphology, crystallinity, bandgap (Eg) and electrical conductivity of ZnO thin films prepared at different heat treatment temperatures were investigated.Atomic force microscopy (AFM) ZnO thin films prepared at 400, 450 and 500 ℃ have rms roughness of 3.3, 2.7 and 3.6 nm, respectively.According to TEM, ZnO thin films contain large amount of nano-particles, The band gap of ZnO was calculated to be 3.3 eV based on the absorption band edge of the film at 373 nm by UV-Vis absorption spectra of the ZnO thin film.According to the current-voltage (IV) curve of the film, And ZnO films prepared at 500 ℃ were 3.3 × 109, 2.7 × 109 and 6.6 × 109Ω · cm respectively. The resistivity of the prepared ZnO films was the lowest because of the higher heat treatment temperature, The purity, density and oxygen adsorption. The resistivity of the thin film with higher purity and higher density is smaller, the adsorption oxygen content increases, the grain boundary barrier increases and the resistivity increases, so the resistance of the ZnO thin film prepared at 450 ℃ under the dual action of the purity and the adsorbed oxygen However, the ZnO thin films prepared at 500 ℃ have the highest resistivity.