埋置量子点应力分布的有限元分析

Finite element analysis on stress distribution in buried quantum dots

通过衬底材料和外延材料的交替生长方式制备出多层排列的自组装量子点超晶格结构.这些埋置量子点的应力/应变场影响着它们的光电性能、压电性能以及力学稳定性.基于各向异性弹性理论的有限元方法,研究了埋置金字塔形应变自组织Ge/Si半导体量子点的应力/应变分布以及流体静应变和双轴应变分布,并与非埋置量子点的应力/应变分布做了比较,指出了它们之间的异同以及覆盖层对量子点应力/应变分布的影响.

The stacked, serf-assembled and vertically aligned quantum dot superlattices are fabricated by alternating growth of substrate and epitaxial materials, the stress/strain fields in the buried quantum dots can influence their optical and piezoelectric properties and mechanical stability. The distributions of stresses, strains, hydrostatic strains and biaxial strains in buried strain serf- assembled Ge/Si semiconductor quantum dot are investigated based on the theory of anisotropy elasticity and also compared with those of free-standing quantum dot. The sameness and difference of the stresses/strains between the buried and the free-standing quantum dots, and the influence of cap layer on the stress/strain fields in quantum dots are given.