GaN/AlN自组织平顶金字塔量子点的应变场分布

Investigation About the Strain Distribution of GaN/AlN Wurtzite Crystal Structure Material Self-organized Truncated Pyramid Shaped Quantum Dots

利用有限元法,研究了GaN/AlN自组织量子点材料的应变场分布。量子点模型采用了实验观察到的六角平顶金字塔形状,材料的弹性常数考虑了晶体材料的Wurtzite结构特性。在晶格失配处理上,采用了三维各项异性伪热膨胀模型。将基于有限元法的计算结果与简化的基于格林函数理论的解析计算结果进行了比较,验证了模型和计算结论的正确性。最后,讨论了各向异性效应对层间量子点垂直对准的影响,指出量子点材料的各向异性效应可以忽略。本文采用的模型没有采用类似解析计算的假设条件,因此在计算精度和可靠性上,要优于格林函数法。

Based on the finite element approach,we investigated the strain field distribution of GaN/AIN self-organized quantum dot. The truncated pyramid shaped quantum dot that has been found in experiment was adopted as the physical model ,and the material elastic constants used in this paper is wurtzite structure. In dealing with the lattice mismatch,we employed a three-dimension anisotropic pseudo thermal expansion of the island. We com- pared the calculated results with that calculated by Green＇s function theory in which lots of assumption is adopted,and the results prove the corrections of our model. In the final, the anisotropic of the material is discussed,and the conclusion is that the anisotropin has no influence on the vertical alignment of inter-layered quantum dots. Our model didn＇t adopt the assumptions used in the Green＇s function approach, so better reliability and precision results are obtained.