Wu Qian, Wang Ping, Liu Yan, Yang Han, Cheng Jingsi, Guo Lixin, Yang Yintang, Zhang Zhiyong
State Key Laboratory of Integrated Services Networks, School of Telecommunications Engineering, Xidian University, Xi'an 710071, China.
School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, China.
Materials (Basel). 2020 Feb 5;13(3):724. doi: 10.3390/ma13030724.
The electronic structures and optical characteristics of yttrium (Y)-doped ZnO monolayers (MLs) with vacancy (zinc vacancy, oxygen vacancy) were investigated by the first-principles density functional theory. Calculations were performed with the GGA+U (generalized gradient approximation plus U) approach, which can accurately estimate the energy of strong correlation semiconductors. The results show that the formation energy values of Y-doped ZnO MLs with zinc or oxygen vacancy (V, V) are positive, implying that the systems are unstable. The bandgap of Y-V-ZnO was 3.23 eV, whereas that of Y-V-ZnO was 2.24 eV, which are smaller than the bandgaps of pure ZnO ML and Y-doped ZnO MLs with or without V. Impurity levels appeared in the forbidden band of ZnO MLs with Y and vacancy. Furthermore, Y-V-ZnO will result in a red-shift of the absorption edge. Compared with the pure ZnO ML, ZnO MLs with one defect (Y, V or V), and Y-V-ZnO, the absorption coefficient of Y-V-ZnO was significantly enhanced in the visible light region. These findings demonstrate that Y-V-ZnO would have great application potential in photocatalysis.
采用第一性原理密度泛函理论研究了具有空位（锌空位、氧空位）的钇（Y）掺杂氧化锌单层（MLs）的电子结构和光学特性。计算采用GGA+U（广义梯度近似加U）方法，该方法能够准确估计强关联半导体的能量。结果表明，具有锌或氧空位（V、V）的Y掺杂ZnO MLs的形成能值为正，这意味着该体系不稳定。Y-V-ZnO的带隙为3.23 eV，而Y-V-ZnO的带隙为2.24 eV，均小于纯ZnO ML以及有或无V的Y掺杂ZnO MLs的带隙。在含有Y和空位的ZnO MLs的禁带中出现了杂质能级。此外，Y-V-ZnO将导致吸收边发生红移。与纯ZnO ML、具有一种缺陷（Y、V或V）的ZnO MLs以及Y-V-ZnO相比，Y-V-ZnO在可见光区域的吸收系数显著增强。这些发现表明Y-V-ZnO在光催化方面具有巨大的应用潜力。
