钾掺杂对纤锌矿型氧化锌电子结构和光学性质的影响

Effect of K Doping on Electronic Structure and Optical Properties of Wurtzite ZnO

针对纯纤锌矿型ZnO禁带宽度较高,不能吸收大部分可见光的问题,采用基于密度泛函理论的第一性原理,构建了钾掺杂ZnO的4种超胞模型,并对4种模型进行几何优化,计算了KXZn1-XO的能带结构、态密度和光吸收性能。结果表明:采用广义梯度近似法(GGA)+U方法计算得到纯氧化锌带隙为3.373 eV,与实验值一致;随着钾掺杂量X的增大,ZnO的禁带宽度Eg出现先增大后减小再增加的现象,KXZn1-XO吸收带发生先蓝移后红移的现象。

Due to the wide band gap of pure wurtzite ZnO,most of the visible light was not be absorbed,four kinds of K-doped ZnO supercell models were constructed by using the first principles based on density functional theory,and four models are geometrically optimized,and then the energy band structure,density of states and light absorption performance of K xZn 1-x O are calculated.The results show that the band gap of pure zinc oxide calculated by general gradient approximation(GGA)+U method is 3.373 eV,which is consistent with the experimental value.With the increase of K doping concentration X,the band gap of ZnO firstly increases,then decreases and then increases,and finally absorption.Edge of K xZn 1-x O shifts blue first and then red.