纤锌矿结构Zn1-xMgxO电子结构及吸收光谱的第一性原理研究

采用第一性原理计算方法，计算了纤锌矿结构Zn_1-xMg_xO(x=0，00625，0125，025)的电子结构及吸收光谱. 计算结果表明，Mg的掺入使ZnO的电子结构发生了较大的改变，与Mg邻近的O原子得到电子的数目明显增大，进而O原子返回部分电子给邻近Zn原子. Zn-O间相互作用减弱，禁带宽度变大，这也从同一合金中Zn4s上移的程度得到证实. 其吸收光谱也随着Mg的掺入出现蓝移现象，其吸收边对应波长分别为379， 关键词： 第一性原理计算 电子结构 吸收光谱 纤锌矿结构ZnO

First-principles calculation on the electronic structure and absorption spectrum of the wurtzite Zn1-xMgxO alloys

The electronic structure and absorption spectrum of the wurtzite Zn_1-xMg_xO(x=0, 00625, 0125, 025)　alloys have been calculated by means of the first-principles method. The doping of magnesium leads to an apparent change of the electronic structure of ZnO. The electron density of the oxygen atoms near the magnesium atom increases obviously, and the oxygen atoms transfer some of the electrons to Zn atoms nearby. This weakens the interactions between zinc and oxygen atoms, the band gap becomes broader, which has been validated by the extent of shift of Zn 4s in the same alloys. Theoretical calculation also reveals a blue shift in the absorption spectrum of Mg-doped ZnO, and the absorption edges were located at 379，366，357 and 333nm, respectively, with increasing doping of magnesium in ZnO. The results are discussed in detail.