基于第一性原理的Ga-Eu共掺ZnO光电性质的研究

采用基于密度泛函理论的第一性原理方法,分析了Ga-Eu共掺杂ZnO(GEZO)结构的能带结构、态密度、马利肯布居分布以及光学性质。结果表明,计算得到的晶格常数及带隙与实验值一致。Ga,Eu的掺入贡献了导电载流子,使体系的电导率增强。费米能级进入导带,呈现n型导电。从态密度中可知费米能级处出现了由Eu的4f态引入的杂质带,Ga也在导带底处贡献了4p和4s态。原子和键的平均马利肯布居分布表明,Ga,Eu原子的掺入增强了键的离子性。光学性质方面,Ga,Eu的掺入使得介电函数实部和虚部的峰位向低能区转移,吸收率和反射率在可见光区均有提高。

Investigation on Electronic and Optical Properties of Ga-Eu Codoped ZnO Based on The First Principle

The band structure, density of states, Mulliken population analysis and optical properties of Ga-Eu codoped ZnO structure were calculated by using the first principles method based on density functional theory. The results reveal that the calculated lattice constants and band gaps agree well with the experimental values. The incorporation of Ga and Eu atoms provide a large amount of free carriers, enhancing the conductivity of the system. At the same time, the Fermi level enters the conduction band and exhibits n-type conductivity. Besides, the density of states show that the impurity band introduced by the 4f state of Eu appears at the Fermi level, and the 4p state and the 4s state of Ga atom also contribute to the bottom of the conduction band. What''s more, the Mulliken atomic and bond populations of Ga-Eu codoped ZnO indicates that the doping of Ga and Eu atoms enhances the ionicity of the bonds. Lastly, the Ga and Eu atoms cause the peaks of the real and imaginary parts of the dielectric function to shift to the low energy region, and the absorption and reflectivity increase in the visible light region.