Reaction kinetic model of height selection in heteroepitaxial growth of quantum dots

摘要

A reaction kinetic model is proposed for height selection of heteroepitaxially growing nanometer-thick quantum dots. The model describes the growth by a set of rate equations for the combined size and height distributions of the dots. In addition to nucleation and growth, the model includes a coarse-grained conversion rate incorporating kinetics of height changes. With suitably chosen rate coefficients the model reproduces qualitatively the experimentally observed height-selected size distributions and their evolution. The results support the view that the height selection and the form of the size distribution both result from the oscillating energy barrier for the transformation of dots of different heights, and this transformation barrier is considerably larger in magnitude than oscillations in the electronic energy due to quantum well states in the dot.