Nano Science and Technology Institute
Nanotech 2002 Vol. 2
Nanotech 2002 Vol. 2
Technical Proceedings of the 2002 International Conference on Computational Nanoscience and Nanotechnology
Chapter 11: Mechanical Properties at the Nanoscale

Size Effects and Scaling in Misfit Dislocation Formation in Self Assembled Quantum Dots

Authors:L.H. Friedman, D.M. Weygand and E. van der Giessen
Affilation:University of Groningen, LN
Pages:271 - 274
Keywords:dislocations, modelling, stress-concentration, quantum dots, self-assembly
Abstract:Growth islands due to large mismatch strain arising in Stranski-Krastanow (SK) and Volmer-Weber (VW) film growth can be used to produce large arrays of quantum dots. This same mismatch strain may also cause misfit dislocations to form, presenting a quality control problem.Johnson and Freund (J. Appl.Ph ys.81 (9), 1997, p6081) developed a two-dimensional model of mis-fit dislocation nucleation in SK and VW growth islands whereby they predict a power-law relation between mis-fit strain, em, and the minimum island size to nucleate a misfit dislocation, Rc: Rc, where l < 1 is a function of the island-substrate contact angle. This problem is treated here in three dimensions as an application of a numerical dislocation simulation using the finite element method to take proper boundary conditions into account. The predictions are analyzed in the context of the Johnson–Freund model, and modification of the power-law is shown to be necessary.
Size Effects and Scaling in Misfit Dislocation Formation in Self Assembled Quantum DotsView PDF of paper
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