论文标题
GE和GE $ _ {0.8} $ si $ _ {0.2} $中的谦虚缺陷的电子结构
Electronic structure of Humble defects in Ge and Ge$_{0.8}$Si$_{0.2}$
论文作者
论文摘要
已知组IV钻石结构元素可容纳各种平面缺陷，包括C和{001}中的{001}平面缺陷，{001}，{111}和{113}平面缺陷。在{001}平面缺陷中，最近在SI/GE Alloys中也观察到了在GE中出现一段时间的不起眼缺陷，但其电子结构的细节仍然很熟悉。在这里，我们执行第一原理密度计算，以研究GE和GE $ _ {0.8} $ si $ _ {0.2} $中的谦虚缺陷。我们还测量了Si l $ _ {2,3} $ - 边缘电子能量损失光谱，均处于缺陷和宽大区域，远离缺陷，并与我们的第一原则计算中相应的SI位点上的理论计算进行比较。我们发现，该理论中包含核心孔效应对于重现观察到的l $ _ {2,3} $ edge Spectra，并且一旦将它们包括在内，结果就可以为不同类型的局部原子键合环境提供一组指纹，以$ _ {0.8} $ _ {0.8} $ si $ _ $ _ {0.2} $。我们的第一原理计算表明，不起眼的缺陷具有扩大电子带隙的趋势，这可能在带工程中具有潜在用途。还讨论了将混合功能用于改进这些系统中频带隙的描述。
The group-IV diamond-structure elements are known to host a variety of planar defects, including {001} planar defects in C and {001}, {111} and {113} planar defects in Si and Ge. Among the {001} planar defects, the Humble defect, known for some time to occur in Ge, has recently also been observed in Si/Ge alloys, but the details of its electronic structure remain poorly understood. Here we perform first-principles density functional calculations to study Humble defects in both Ge and Ge$_{0.8}$Si$_{0.2}$. We also measure the Si L$_{2,3}$-edge electron energy loss spectra both at the defect and in a bulk-like region far from the defect, and compare with theoretical calculations on corresponding Si sites in our first-principles calculations. We find that inclusion of core-hole effects in the theory is essential for reproducing the observed L$_{2,3}$ edge spectra, and that once they are included, the results provide a set of fingerprints for different types of local atomic bonding environments in Ge$_{0.8}$Si$_{0.2}$. Our first-principles calculations reveal that the Humble defects have a tendency to enlarge the electronic band gap, which may have potential uses in band engineering. The use of hybrid functionals for an improved description of the band gap in these systems is also discussed.
