Abstract A heterostructure with variable Al contents have been used in emission layer of photocathode to improve quantum efficiency, because difference in Al content of adjacent sublayers would generate a built-in electric field to help electron transport. In this article, based on use of first principles, we have studied structure, stability and electronic features of AlxGa1−xN/GaN heterostructure. The AlxGa1−xN/GaN heterostructure is obtained by finding the most stable stacking situation of bilayer GaN and introducing Al content in bottom layer. The cohesive energy, band structure and density of states are calculated. The results revel that introduction of Al content can increase cohesive energy of multilayer GaN and make system more stable. It will also magnify band-gap of heterostructure. The results of DOS show that increasing of Al content in AlxGa1−xN monolayer enhance contribution of Al s-orbitals and p-orbitals, while contribution of Ga s-orbitals and p-orbitals decline. Finally, through analysis of stability and electronic properties of AlxGa1−xN/AlyGa1−yN heterostructure, we have found that influence of size of Al contents far exceeds that of position of Al atom.

中文翻译：

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可变Al含量二维AlxGa1-xN/GaN异质结稳定性和电子特性对比研究

摘要 在光电阴极的发射层中使用了具有可变铝含量的异质结构以提高量子效率，因为相邻子层的铝含量不同会产生内建电场来帮助电子传输。在本文中，我们基于第一性原理，研究了 AlxGa1-xN/GaN 异质结构的结构、稳定性和电子特性。AlxGa1-xN/GaN异质结构是通过寻找双层GaN最稳定的堆叠情况并在底层引入Al含量来获得的。计算内聚能、能带结构和态密度。结果表明，Al含量的引入可以提高多层GaN的内聚能，使系统更加稳定。它还将放大异质结构的带隙。DOS的结果表明，AlxGa1-xN单层中Al含量的增加增强了Al s-轨道和p-轨道的贡献，而Ga s-轨道和p-轨道的贡献下降。最后，通过对AlxGa1-xN/AlyGa1-yN异质结构的稳定性和电子性质的分析，我们发现Al含量大小的影响远远超过Al原子位置的影响。