Migration of Mg and other interstitial metal dopants in GaN
Migration of Mg and other interstitial metal dopants in GaN
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DOI：
10.1002/pssr.201700081
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发表时间：
2017-06
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影响因子：
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通讯作者：
Giacomo Miceli;Alfredo Pasquarello
中科院分区：
文献类型：
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作者：
Giacomo Miceli;Alfredo Pasquarello
通过密度泛函计算，研究了镁在纤锌矿氮化镓中迁移的最小能量路径。该研究还包括Li， Na和Be掺杂剂，以检查对掺杂剂种类的大小和电荷的依赖。在所有考虑的情况下，杂质像离子一样扩散，没有任何局部电荷的倾向。Li、Mg以及一定程度上的Na在GaN中几乎是各向同性扩散的，平均扩散势垒分别为1.1、2.1和2.5 eV。相反，在垂直和平行于c轴的扩散路径上，Be表现出明显的各向异性，能垒分别为0.76和1.88 eV。扩散势垒一般随离子电荷和离子半径的增加而增加，但它们之间的相互作用并非微不足道。计算出的Mg迁移势垒与最近β−发射通道实验的估计值一致。
The minimum energy paths for the migration of interstitial Mg in wurtzite GaN are studied through density functional calculations. The study also comprises Li, Na, and Be dopants to examine the dependence on size and charge of the dopant species. In all cases considered, the impurities diffuse like ions without any tendency of localizing charge. Li, Mg, and to some extent Na, diffuse almost isotropically in GaN, with average diffusion barriers of 1.1, 2.1, and 2.5 eV, respectively. Instead Be shows a marked anisotropy with energy barriers of 0.76 and 1.88 eV for diffusion paths perpendicular and parallel to the c‐axis. The diffusion barrier generally increases with ionic charge and ionic radius, but their interplay is not trivial. The calculated migration barrier for Mg is consistent with the values estimated in a recent β− emission channeling experiment.