硅酸锌的电子结构

采用局域密度泛函理论和第一性原理的方法,计算四方结构和六角结构硅酸锌的平衡晶格常数、电子态密度和能带结构。计算结果表明,四方结构硅酸锌的平衡晶格常数为0.71048nm,六角结构为1.40877nm,两者与实验值的误差均在1%左右。态密度图显示,主要电子态分布在-7.18～0.00eV和2.79～10.50eV两个能量区域;同时,不同元素电子对导带和价带有不同贡献,其中氧的p态电子对价带顶贡献最大,锌的s态电子对导带底贡献最大。能带计算表明,四方与六角结构硅酸锌均为直接带隙半导体,禁带宽度分别为2.66,2.89eV。

Electronic Structures of Zn2SiO4

The electronic structures of the tetragonal and hexagonal Zn_2SiO_4 with super cells of 28 and 126 atoms were calculated by Vienna ab-initio Simulation Package with ultrasoft pseudopotentials.The calculated equilibrium lattice constants agree much well with the experimental values.Using the optimized equilibrium lattice constants,the densities of states and energy band structures were further calculated.The total densities of states of both structures show the valence and conduction bands.By analyzing the partial densities of states,the contributions of different electron states in different atoms are estimated.The d states of Zn and p states of O mostly contribute to the top of the valence band,and the s states of Zn make major effects on the bottom of conduction band.The similar densities of states in the mass of the two structures suggest that both structures have the similar electronic and optical properties.Moreover,the calculated energy band structures show that the tetragonal and hexagonal Zn_2SiO_4 have direct energy band gaps,which are promising semiconductors for short wavelength optoelectronic devices.