Electronic structure and optical properties of Al0.25Ga0.75N with point defects and Mg-defect complexes
Electronic structure and optical properties of Al0.25Ga0.75N with point defects and Mg-defect complexes
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点缺陷和Mg缺陷复合体Al0.25Ga0.75N的电子结构和光学性质
DOI：
10.1007/s11082-018-1328-0
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发表时间：
2018-01
影响因子：
3
通讯作者：
Rao Weifeng
中科院分区：
文献类型：
--
作者：
Yang Mingzhu;Fu Xiaoqian;Guo Jing;Rao Weifeng
为了研究点缺陷对Al0.25Ga0.75N光电性能的影响，建立了具有不同缺陷的本征晶体和掺镁Al0.25Ga0.75N晶体模型。基于第一性原理计算，计算了地层能量、电子结构和光学性质。结果表明，在p型条件下，N空位（VN）具有最小的地层能，并始终充当供体。在n型条件下，Ga空位（VGa）始终充当受体，具有最小的形成能。间质性N缺陷（Ni）、Ga反位缺陷（GaN）和N反位缺陷（NGa）在p型条件下为供体，在N型条件下为受体。n型缺陷VNand与p型Mg杂质形成配合物，配合物稳定存在于Al0.25Ga0.75N晶体中，具有较高的结合能。含mgga - vn晶体的费米能级进入带隙，含mgga - gain晶体的费米能级进入导带，表明它们的p型性质受到破坏。与无缺陷的本征晶体相比，缺陷晶体的介电函数虚部峰均向低能区偏移。此外，缺陷晶体的金属反射区和吸收边明显向较低能区移动，表明缺陷晶体的带隙较小。
To study the influence of point defects on optoelectronic properties of Al0.25Ga0.75N, models of intrinsic and Mg doped Al0.25Ga0.75N crystals with various defects were built. Based on first-principles calculations, formation energies, electronic structure, and optical properties were calculated. Results show that N vacancy (VN) owns the smallest formation energy in p-type condition, and it always acts as a donor. Ga vacancy (VGa) always acts as an acceptor and owns the smallest formation energy in n-type condition. Interstitial N defect (Ni), Ga antisite defect (GaN), and N antisite defect (NGa) act as donors in p-type condition while they act as acceptors in n-type condition. N-type defects VNand Gaiform complexes with p-type Mg impurity, and the complexes exist stably in Al0.25Ga0.75N crystal with high binding energy. The Fermi level of crystal with MgGa–VNmoves into band gap and that with MgGa–Gaienters into conduction band, showing that their p-type property is damaged. Compared with intrinsic crystal without defects, the peaks of imaginary part of dielectric function for the defective crystals all shift to lower energy region. Besides, the metal reflective regions and the absorption edges of crystals with defects shift to lower energy region significantly, showing that the band gaps of defective crystals are smaller.
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影响因子：
3.1
作者：
Jing Guo;Minhua Zhou;J. Zhao;Lei Zhou;Liansong Xiong
通讯作者：
Jing Guo;Minhua Zhou;J. Zhao;Lei Zhou;Liansong Xiong
影响因子：
3.1
作者：
Sihao Xia;Lei Liu;Yike Kong;Meishan Wang
通讯作者：
Sihao Xia;Lei Liu;Yike Kong;Meishan Wang
影响因子：
3
作者：
H. Ryu
通讯作者：
H. Ryu
影响因子：
6.7
作者：
Sumiya, Masatomo;Kamo, Yutaro;Fuke, Shunro
通讯作者：
Fuke, Shunro
影响因子：
4
作者：
Neugebauer, J;Van de Walle, CG
通讯作者：
Van de Walle, CG