Abstract

GONZALEZ, Diego Luis. One-dimensional Point-island Model With Hindered Aggregation: A Kinetic Approach. rev. cienc. [online]. 2014, vol.18, n.2, pp.81-93. ISSN 0121-1935.

The effect of hindered aggregation on the time evolution of the average densities of islands and monomers in a one-dimensional point-island model with critical nucleus size i is studied. In the model proposed, the aggregation of a monomer to an island with size larger than i is hindered by an inverse Ehrlich-Schwoebel barrier ΔEES which has a characteristic length les. For les = 0 the stable islands behave as perfect sinks for monomers and the aggregation is dominated by diffusion. On the other hand, for les →∞­the islands behave as reflective boundaries and the aggregation is limited by reaction. A mean-field model is proposed to determine the time evolution of the mean densities of islands (N) and monomers (N1). For the cases i = 1, 2 and 3, the capture kernels are determined from the numerical results obtained through kinetic Monte Carlo simulations. It is found that, in the aggregation regime, the time evolution of N y N1 depends strongly on les. In spite of this, with the suitable choice of the capture kernels it is possible to describe successfully the time evolution of both quantities. In the aggregation regime, the typical time of nucleation τn and aggregation τa satisfy the relation τa« τn for arbitrary values of les, which implies that in this regime an aggregation is more likely than a nucleation.‑

Keywords : epitaxial growth; hindered aggregation and point-island model.

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