Kinetic Monte Carlo simulation of quantum-dot nucleation
in PbSe/PbEuTe multilayers

M. Mixa¹, V. Holy¹, G. Springholz², D. Lugovyy²

¹Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Praha, Czech Republic

²Institute of Semiconductor Physics, Johannes Kepler University, Altenbergerstr. 69, A-4040 Linz, Austria

martin.mixa@centrum.cz

PbSe/PbEuTe quantum-dot multilayer is an interesting example of a self-organized semiconductor nanostructure. In this system the self-assembly phenomenon is caused by the elastic deformation of crystal lattice due to the lattice mismatch between both materials. Depending on the thickness of the PbEuTe spacer layer, three different arrangements of the PbSe dot superlattice are experimentaly observed (vertical and trigonal arrangements of the dots as well as non-correlated mode of dot positions).

In our theoretical study of the epitaxial growth and the self-organization processes in this system we use the kinetic Monte Carlo method for the simulation of the PbSe dot nucleation. The nucleation probability of a quantum dot at the surface of a particular PbSe layer is influenced by the local chemical potential of migrating adatoms and consequently by the local surface elastic energy induced by the dots on the PbSe/PbEuTe interfaces buried below the surface. This energy distribution is taken into account for the movement simulation of atoms deposited on the growing surface. Changing the spacer layer thickness we obtain the same dot-superlattice arrangements as in the experiments.

Acknowledgement

This work is a part of the research plan MSM 0021620834 that is financed by the Ministry of Education of the Czech Republic. The work was also supported by the Grant Agency of Academy of Sciences of the Czech Republic (project KAN400100652).