Demonstration of the donor characteristics of Si and O defects in GaN using hybrid QM/MM
Demonstration of the donor characteristics of Si and O defects in GaN using hybrid QM/MM
复制标题
使用混合 QM/MM 演示 GaN 中 Si 和 O 缺陷的施主特性
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
A. Sokol
中科院分区：
文献类型：
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作者：
Zijuan Xie;Y. Sui;J. Buckeridge;C. Catlow;T. Keal;P. Sherwood;A. Walsh;D. Scanlon;S. Woodley;A. Sokol
利用混合量子力学/分子力学（QM/MM）嵌入簇计算，我们研究了氮化镓中硅和氧掺杂剂的稳定性。利用传统的热化学、动力学交换和相关密度泛函（B97‐2和BB1k）在两个理论水平上计算了Si在Ga位点上和O在N位点上的形成能。我们证实了这些取代缺陷的浅供体性质。我们发现Si和O的0/1+跃迁水平都位于传导带的底部以上，这与之前基于超级单体的模拟结果一致。在相关实验结果的背景下讨论了该伪影的起源，并展示了如何在与实验良好一致的情况下确定正确的间隙浅能级。
Using hybrid quantum mechanical/molecular mechanical (QM/MM) embedded cluster calculations, we investigate the stabilization of silicon and oxygen dopants in GaN. Formation energies of Si on a Ga site and O on an N site are calculated at two levels of theory using conventional thermochemical and kinetic exchange and correlation density functionals (B97‐2 and BB1k). We confirm the shallow donor nature of these substitutional defects. We find that the 0/1+ transition levels for both Si and O species lie well above the bottom of the conduction band, in agreement with previous supercell‐based simulations. The origin of this artifact is discussed in the context of relevant experimental results and we show how correct in‐gap shallow levels can be ascertained in good agreement with experiment.