Zn1-xMgxO电子结构及光学性质的第一性原理GGA+U方法研究

Mg掺杂ZnO形成的固溶体Zn_1-xMg_xO（ZMO）（0 ≤ x ≤ 0.25）是一种带隙较宽、电子学性质可调控的半导体材料，在薄膜太阳电池及光电设备的透明电极等方面具有重要的应用价值。基于密度泛函理论下的第一性原理超软赝势方法，采用GGA+U计算了ZMO的电子结构和光学性质。计算结果表明，随着x值的增加，ZMO的禁带宽度由x=0时的3.32 eV增加到x=0.25时的3.78 eV；光吸收边及反射谱和能量损失谱均发生明显蓝移，峰值存在于紫外光区。计算结果与实验结论相符合。

First-principles GGA+U Investigation on The Electronic Structure and Optical Properties of Zn1-xMgxO

Mg substitution in ZnO can form ternary alloys Zn_1-xMg_xO(ZMO)(0 ≤ x ≤ 0.25)which has wide band gap and tunable electronic properties. So ZMO has a large application in transparency electrode of thin-film solar cells and optoelectronic device. The electronic structure and optical properties of ZMO ternary alloys were calculated using first-principles calculations based on the density functional theory combined with GGA+U approach. The calculation results show that the doping of magnesium leads to an apparent change of the electronic structure of ZMO. With Mg concentration increasing, the band gap of ZMO widens from 3.32 eV(x=0) to 3.78 eV(x=0.25). In addition, the absorption edge exhibits a blue shift with Mg concentration increasing. At the same time, the reflectivity and loss-function show mainly in the ultra-violet region, which is similar to those of optical absorption. The calculation results are in good agreement with the experiment.