Comparative analysis of pyramidal and wedge-like quantum dots formation kinetics in Ge/Si(001) system

In this work complex mathematical model for calculation of dependencies on growth conditions of parameters of self-organized quantum dots (QDs) of Ge on Si grown by the method of molecular beam epitaxy (MBE) is described. Calculations on pyramidal and elongated islands formation energies in Ge/Si(001) system with respect to surface energy, elastic strains relaxation and attraction of atoms to substrate decreasing are done. On the basis of well-known model based on generalization of classical nucleation theory it is shown that wedge-like clusters form later than pyramidal but begin to dominate in the QDs massive on the later stages of growth. Conclusions from the described theory correspond to the experimental observations. (C) 2013 Elsevier B.V. All rights reserved.