Dependence of elastic strain field on the self-organized ordering of quantum dot superlattices

Yumin Liu1,2), Zhongyuan Yu1,2), and Yongzhen Huang3) 1) School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China 2) Key Laboratory of the Ministry of Education of China for Optical Communication and Lightwave Technologies, Beijing 100876, China 3) State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083, China

摘 要：A systematic investigation of the strain distribution of self-organized, lens-shaped quantum dot in the case of growth di- rection on （001） substrate was presented. The three-dimensional finite element analysis for an array of dots was used for the strain calculation. The dependence of the strain energy density distribution on the thickness of the capping layer was investigated in detail when the elastic characteristics of the matrix material were anisotropic. It is shown that the elastic anisotropic greatly influences the stress, strain, and strain energy density in the quantum dot structures. The anisotropic ratio of the matrix material and the combina- tion with different thicknesses of the capping layer, may lead to different strain energy density minimum locations on the capping layer surface, which can result in various vertical ordering phenomena for the next layer of quantum dots, i.e. partial alignment, ran- dom alignment, and complete alignment.

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