Nanotech 2002 Vol. 2
Nanotech 2002 Vol. 2
Technical Proceedings of the 2002 International Conference on Computational Nanoscience and Nanotechnology

Mechanical Properties at the Nanoscale Chapter 11

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

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.

ISBN: 0-9708275-6-3
Pages: 504

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