Kong Bo, An Xin-You, Zeng Ti-Xian, Zhang Jihua
College of Physics and Space Sciences, China West Normal University, Nanchong 637002, China.
Phys Chem Chem Phys. 2020 Apr 14;22(14):7474-7482. doi: 10.1039/c9cp06094d. Epub 2020 Mar 27.
In this study, the formation energies and electronic properties of six native defects as well as H impurities in wurtzite (wz) CdSe are systematically investigated using hybrid density functional calculations. It is shown that native defects, including antisite Cd and interstitial Cd, may be sources of the unintentional n-type conductivity in CdSe under Se-poor conditions; meanwhile, the vacancy defect V is not a good donor. However, when the common H impurity is considered, it is suggested that both the substitutional impurity H and the interstitial impurity H are the dominant and effective origins of the unintentional n-type conductivity in Se-poor conditions. However, unintentional p-type conductivity in CdSe is challenging to form regardless of the growth conditions. Moreover, hybrid functional calculations of the electronic structures show that the six native point defects and the extrinsic impurities H and H will cause more or fewer changes in the band gap. Among all considered defects and impurities, it is found that only the interstitial defect Cd introduces impurity levels into the band gap. In particular, the present hybrid functional calculations theoretically affirm that the vacancy defect V in CdSe can induce a 2 μ magnetic moment; however, other native defects will not introduce any magnetic moment.
在本研究中，利用杂化密度泛函计算系统地研究了纤锌矿（wz）CdSe中六种本征缺陷以及H杂质的形成能和电子性质。结果表明，本征缺陷，包括反位Cd和间隙Cd，可能是贫Se条件下CdSe中非故意n型导电性的来源；同时，空位缺陷V不是一个好的施主。然而，当考虑常见的H杂质时，表明取代杂质H和间隙杂质H都是贫Se条件下非故意n型导电性的主要和有效来源。然而，无论生长条件如何，CdSe中形成非故意p型导电性都具有挑战性。此外，电子结构的杂化泛函计算表明，六种本征点缺陷以及外在杂质H和H会或多或少地导致带隙变化。在所有考虑的缺陷和杂质中，发现只有间隙缺陷Cd在带隙中引入杂质能级。特别是，目前的杂化泛函计算从理论上证实了CdSe中的空位缺陷V可以诱导2μ的磁矩；然而，其他本征缺陷不会引入任何磁矩。
