Al掺杂ZnO粉体的第一性原理计算及微波介电性质

采用基于密度泛函理论的第一性原理平面波超软赝势方法，计算了本征ZnO和Al掺杂ZnO的能带结构和介电常数，又采用固相反应法在６００　℃保温1.5 h分解得到ZnO和Al掺杂ZnO粉体．X射线衍射（XRD）对所得粉体的结构进行表征，X射线光电子谱（XPS）对掺入的Al的形态进行分析，矢量网络分析仪在8.2—12.4 GHz测试样品的微波介电性能．结果表明，Al掺杂后ZnO的晶胞体积基本不变，费米能级进入导带．实验所得粉体均具有ZnO的纤锌矿结构，Al是以替位杂质的形式进入ZnO晶格．实验与计算结果相比，都表 关键词： Al掺杂ZnO 介电性质 能带结构 第一性原理

First-principles calculation of microwave dielectric properties of Al-doping ZnO powders

The band structure and dielectric properties of the pure ZnO and the Al-doped ZnO were studied by using a first-principle uhrasoft pseudopotential approach of the plane wave based on the density functional theory. The pure ZnO and the Al-doped ZnO powders were prepared via the solid state reaction at 600℃ with holding time of 1.5 h. The prepared powders were characterized by X-my diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The dielectric parameters were determined by the vector network analyzer in the frequency range of 8.2-12.4 GHz. Results show that the volume of super-cell has no obvious change and the Fermi energy level is introduced into conduction band through introducing A1 ions. XRD patterns indicate that all the samples have pure wurtzite structure of ZnO. It is found that A1 ions form the substitutional impurity in ZnO crystal according to the result of XPS. The experimental results show that both the real part ε' and imaginary part ε" of permittivity of the samples are increased by Al doping, in agreement with the result of calculation.