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.