A perturbation theory for calculating strain distributions in heterogeneous and anisotropic quantum dot structures

作者：Wang J^*; Chu H J

来源：Journal of Applied Physics, 2006, 100(5).

DOI：10.1063/1.2337851

• Pyramidal Ge/Si QD structure
• Stiffness tensors
• Strain distribution

By introducing a homogenous comparison material, a perturbation theory based on Green's function is proposed to calculate the strain distribution inside and outside an arbitrarily shaped and anisotropic quantum dot (QD) embedded in an alien infinite medium. This theory removes the limitations of the previous analytical methods which are based upon the assumption that the QD is isotropic and has the same elastic properties as the surrounding medium. The numerical results for a truncated pyramidal Ge/Si QD structure demonstrate that the anisotropy of the materials and the difference between the stiffness tensors of the QD and the matrix have a significant influence on the strain field. It is found that the first-order approximate solution obtained by the proposed method can reduce the relative difference of the strain fields induced by the isotropic approximation from 30% to 6%. Moreover, it is shown that the strain fields obtained by the proposed method with the second-order approximate solution are very accurate for the Ge/Si QD structure.

• 出版日期2006
• 单位北京大学