Growth features and nucleation mechanism of Ga1-x-yInxAlyN material system on GaN substrate

The continuum elasticity model is applied to investigate quantitatively the growth features and nucleation mechanism of quantum dots, nanopits, and joint QDs&#8211;nanopits structures in GaInAlN quasyternary systems. We have shown that for GaInAlN material system at the critical strain of <i>&#949;</i>^* = 0.039 the sign of critical energy and volume is changed. We assume that at <i>&#949;</i> = <i>&#949;</i>^* the mechanism of the nucleation is changed from the growth of quantum dots to the nucleation of nanopits. Obviously, at small misfit (<i>&#949;</i> < <i>&#949;</i>^*), the bulk nucleation mechanism dominates. However, at <i>&#949;</i> > <i>&#949;</i>^*, when the energy barrier becomes negative as well as a larger misfit provides a lowbarrier path for the formation of dislocations, the nucleation of pits becomes energetically preferable. The free energy of mixing for Ga_1-x-yIn_xAl_yN quasiternary system was calculated and studied and its 3D sketch was plotted.