Properties of amorphous GaN from first-principles simulations
Properties of amorphous GaN from first-principles simulations
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DOI：
10.1103/physrevb.84.075216
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发表时间：
2011-08-15
影响因子：
3.7
通讯作者：
Drabold, D. A.
中科院分区：
文献类型：
--
作者：
Cai, B.;Drabold, D. A.
非晶GaN（a-GaN）模型由第一性原理模拟获得。我们比较了四个a-GaN模型产生的“熔化和淬火”和计算机炼金术的方法。我们发现，大多数原子往往是四重的，和化学有序的连续随机网络是理想的结构，a-GaN虽然有一些配位缺陷。在电子结构方面，预测的差距小于1.0 eV，低估了通常由密度泛函计算。我们观察到一个高度本地化的价尾和一个显着的离域指数传导尾在所有模型产生。基于这些结果，我们推测在n型和p型掺杂的潜在差异。讨论了尾态和缺陷态的结构起源。计算了振动态密度和介电函数，与实验结果基本一致。
Amorphous GaN (a-GaN) models are obtained from first-principles simulations. We compare four a-GaN models generated by "melt-and-quench" and the computer alchemy method. We find that most atoms tend to be fourfold, and a chemically ordered continuous random network is the ideal structure for a-GaN albeit with some coordination defects. Where the electronic structure is concerned, the gap is predicted to be less than 1.0 eV, underestimated as usual by a density functional calculation. We observe a highly localized valence tail and a remarkably delocalized exponential conduction tail in all models generated. Based upon these results, we speculate on potential differences in n- and p-type doping. The structural origin of tail and defect states is discussed. The vibrational density of states and dielectric function are computed and seem consistent with experiment.