氧化锌电子结构的压力效应的理论研究

基于平面波函数密度泛函理论研究了不同压力条件下纤锌矿结构氧化锌的晶格结构和电子结构。计算结果表明,氧化锌的晶格参数和Zn—O键长随外压力的增加先增大后逐渐减小,晶胞纵横轴长之比增大,晶格对称性保持不变;带隙类型均为直接带隙,其宽度随外压力增加先降低后逐渐增大,零压力下其存在着0.908eV的直接带隙,在最大压力100GPa下其带隙达0.993eV;费米能级附近的状态密度随压力增加有增大的趋势,电子局域化趋势明显。分析结果表明,随着外压力的增加,氧化锌费米能级下方附近的载流子有效质量先增大后减小;导带的载流子有效质量均较小。外界加力还改变了氧化锌体系的电子分布情况。

Theoretical Investigation of Influences of Pressure on Electronic Structure of Zinc Oxide

The crystal structure and electronic sturcture of the Wurtzite type ZnO at different exoteric pressures have been investigated based on the density functional theory calculations of the plane wave. The results show that the lattice parameters of ZnO and ZnO bond length are increased firstly and then decreased with the increase of the external pressure, the ratio of vertical and horizontal axis increases, while the symmety of the structure remain unchanged. The band gaps are all direct gap, the gap width decreases firstly and then increases along with increasing the exoteric pressure. The band gap is 0.908 eV for the un pressed ZnO and the band gap of the ZnO at 100 GPa is increased to 0.993 eV. The density of states near Fermi level can be increased by increasing the exoteric pressure and the localization of the electrons can be enhanced. The analyzing results has shown that the effective mass of the carriers under the Fermi level can be enhanced firstly and then depressed by increasing the exoteric pressure, the effective mass of the carriers above the Fermi level is slightly light. The distribution of the electrons at different orbitals can be modulated by altering the exoteric pressure.