Analysis of strained nitride quantum dots as threading dislocation filters

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.

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► We predict the critical condition for strained QDs acting as dislocation filters.
► Cylindrical and hexagonal truncated pyramidal QDs are discussed.
► QD with threading dislocation is modeled by finite element.
► The energy balance approach includes three interactions and a reasonable barrier.
► Larger and slimmer QDs are more effective to bend the TD.