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Abstract: We calculate the minimum Gibbs free energy of the InAs/InP quantum dot multilayer by combining the method of moving asymptotes and the finite element method. Based on the principle of the least energy, the transition between vertically aligned and anti-aligned quantum dot multilayers is studied. We investigate the influence of quantum dot base size and density on critical spacer thickness for the transition. The study results indicate that the critical thickness increases with the decrease in the density of quantum dots, while the base size of the quantum dot is linear to the critical thickness when the density is given. [Copyright &y& Elsevier]

Abstract: A finite element model is proposed to quantitatively predict the critical condition for a nitride quantum dot to bend threading dislocation to interfacial misfit dislocation. The energy balance approach adopted is based on the elastic residual strain energy and non-elastic dislocation core energy. We find that the critical misfit, beyond which the inclination of threading dislocation is energetically favorable, depends strongly on the shape, size and aspect ratio. The results provide guidelines for the design of quantum dot dislocation filter. [Copyright &y& Elsevier]

Abstract: We present a finite element method to simulate the strain field in InSb/GaSb quantum dots in the framework of anisotropic elasticity, before and after the onset of plastic relaxation. Taking the interaction between dislocation and free surface into consideration, the model directly calculates the residual strain in the dislocated system. Based on the energy balance between the two isolated states, the equilibrium critical size is determined. In the criterion, only the non-elastic dislocation core energy should be considered separately. The results are in satisfactory agreement with experimental data. [Copyright &y& Elsevier]