论文标题
hexagonal si $ _x $ ge $ _ {1-x} $/si $ _y $ ge $ ge $ _ {1-y} $ Alloy Interfaces的乐队阵容
Band lineup at hexagonal Si$_x$Ge$_{1-x}$/Si$_y$Ge$_{1-y}$ alloy interfaces
论文作者
论文摘要
通过多种方法研究了由六角形Si $ _x $ _x $ _x $ _x $ _x $ _x $ _x $ _x $ _x $ _ {1-x} $合金形成的自然和真实带曲线的自然和真实的带曲线，这些方法是通过多种方法进行的：原子质几何的密度功能理论，近似于电子结构的准列处理，用于电子结构的准级处理，不同的带边缘平衡程序和各种轮轴的单元和各种构造单元的组合。我们证明，自然带偏移不受对齐真空水平或分支点能的选择以及使用杂种或tran-blaha功能的选择。在GE富合金之间的界面上，我们观察到具有直接带隙的I型异质特征，而富含Si的连接是I型I型，但具有间接的带隙。伪形化的异质结构的真实带阵容受到两种相邻合金中相反符号的双轴菌株的强烈影响。我们的计算表明，界面的I型特征通过应变降低。为了制备适合有效光电应用的合金杂膜，我们讨论了如何减少GE富合金的压缩双轴菌株。
The natural and true band profiles at heterojunctions formed by hexagonal Si$_x$Ge$_{1-x}$ alloys are investigated by a variety of methods: density functional theory for atomic geometries, approximate quasiparticle treatments for electronic structures, different band edge alignment procedures, and construction of various hexagonal unit cells to model alloys and heterojunctions. We demonstrate that the natural band offsets are rather unaffected by the choice to align the vacuum level or the branch point energy, as well as by the use of a hybrid or the Tran-Blaha functional. At interfaces between Ge-rich alloys we observe a type-I heterocharacter with direct band gaps, while Si-rich junctions are type-I but with an indirect band gap. The true band lineups at pseudomorphically grown heterostructures are strongly influenced by the generated biaxial strain of opposite sign in the two adjacent alloys. Our calculations show that the type-I character of the interface is reduced by strain. To prepare alloy heterojunctions suitable for active optoelectronic applications, we discuss how to decrease the compressive biaxial strain at Ge-rich alloys.
