摘要
The electronic structure and optical properties of Zn1-x BexO alloys were studied using first principle calculation based on density functional theory （DTF）. The results indicate that the band gap of Zn1-x BexO alloys increases as Be composition increases. The major reason is that the valence band maximum （VBM） of O2p has no obvious shift while the conduction band minimum （CBM） of Zn4s shifts to higher energy as x composition increases. Calculated results of the imaginary part of the dielectric function reveal that the peak heights at 2.0 and 6.76eV decrease as x composition increases, which is attributed to the decrease of the Zn3d states after Be substitutes for Zn. Due to the increasing transition probability from VBM of O2p to CBM of Be2s in wurtzite structure BeO,the peak height at 9.9eV is enhanced and its position shifts toward higher energy.
基于密度泛函理论(DFT)第一性原理计算了Zn1-xBexO化合物的电子结构和光学性质.计算结果表明Zn1-xBexO带隙随掺杂浓度的增加而变大.这种现象主要是由于价带顶O2p随掺杂量x的增加几乎保持不变,而Zn4s随掺杂量x的增加向高能端移动.光学介电函数虚部计算结果表明:在2.0,6.76eV位置随掺杂浓度的增加峰形逐渐消失,是由于Be替代Zn导致Zn3d电子态逐渐减少所致;而9.9eV峰形逐渐增强,是由于逐渐形成的纤锌矿结构BeO的价带O2p到导带Be2s的跃迁增加所致.
基金
supported by the National Natural Science Foundation of China(No.60676055)
the State Key Development Programfor Basic Research of China(No.2005CB623605)
the Fund of National Engineering Research Center for Optoelectronic Crystalline Materials(No.2005DC105003)
the Natural Science Foundation of Fujian Province(No.E0320002)~~
