This work introduces an easy and flexible model of implementing the screw dislocation in the finite element analysis, and it could be easily extended to incorporate the surface stress to refine the analysis of nanostructures. Applications to a complete analysis of dislocation dissipation by the image force in GaN nanorods were investigated here. Various shaped nanorods were studied, including top chopped nanorods that have not been studied in other literatures. This work demonstrates the dislocation was dissipated towards the free surfaces more effectively in the cap region of nanorods. This dislocation dissipation mechanism agrees well with the phenomena observed in the experiments carried out here. Image forces were compared for different shaped nanorods. It was proposed to incorporate surface stress into the current model to refine the stress calculation as it was crucial for nanostructures with dimensions less than 10 nm. This work could contribute to nanostructure design and provide guidance for the fabrication of dislocation-free nanostructures.

Finite Element Modeling of Dislocation in Solids and its Applications to the Analysis of GaN Nanostructures. W.Ye, B.Paliwal, W.H.Goh, M.Cherkaoui, A.Ougazzaden: Computational Materials Science, 2012, 58, 154–61