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arXiv · 0912.0053

Kinetic Monte Carlo simulation of shape transition in strained quantum dots

Chi-Hang Lam
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Abstract

The pyramid-to-dome transition in Ge$_{x}$Si$_{1-x}$ on Si(100) initiated by step bunching on pyramidal quantum dots is atomistically simulated using a novel multi-state lattice model incorporating effective surface reconstructions. Results are explained by a simple theory based on a shallow island approximation. Under given deposition conditions in $d$ dimensions, the shape transition is shown to occur at island size $n_c$ following $n_c^{1/d} \propto x^{-\zeta}$ independent of temperature and deposition rate, where $\zeta\alt 2$ and $x$ is the actual Ge concentration in the island. The transition has an energy barrier dominated by the facet interface energy. Fast deposition however can out-run and delay the transition to larger island sizes.

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Chi-Hang Lam. 2009-12-01. Kinetic Monte Carlo simulation of shape transition in strained quantum dots. https://arxiv.org/abs/0912.0053

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