Experimental and theoretical investigation on the structural properties of GaN grown on sapphire
Experimental and theoretical investigation on the structural properties of GaN grown on sapphire
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DOI：
10.1063/1.1618379
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发表时间：
2003-10
影响因子：
4
通讯作者：
J. Ohta;H. Fujioka;M. Oshima;K. Fujiwara;A. Ishii
中科院分区：
文献类型：
--
作者：
J. Ohta;H. Fujioka;M. Oshima;K. Fujiwara;A. Ishii
我们通过脉冲激光沉积和第一性原理计算研究了第三族氮化物在c面蓝宝石衬底上的生长机理。实验表明，氮化物和蓝宝石的面内取向关系为[10-10]nitride//[11-20]sapphire，氮化物薄膜在大多数情况下具有N极性。我们已经发现，富Al的AlN缓冲层的插入有效地将GaN晶体从N极性转变为Ga极性，尽管富Ga的GaN缓冲层不会引起极性的变化。对蓝宝石平板表面吸附原子的能量计算很好地解释了平面内取向和极性变化等实验结果。
We have investigated the growth mechanisms of group-III nitrides on c-plane sapphire substrates with experiments by pulsed-laser deposition and first-principles calculations. It has been experimentally revealed that the in-plane alignment between the nitrides and sapphire is [10-10]nitride//[11-20]sapphire and the nitride films have the N polarity for the most cases. We have found that the insertion of an Al-rich AlN buffer layer effectively turns over the GaN crystals from the N polarity to the Ga polarity, although the Ga-rich GaN buffer layer does not cause change in the polarity. The theoretical energy calculations of a sapphire slab with an adatom explain the experimental results, such as the in-plane alignment and the polarity change, quite well.