Dot size dependence of vertical and lateral ordering in self-organized $PbSe/Pb1−xEuxTe$ quantum-dot superlattices

Self-organized vertical and lateral ordering in $PbSe/Pb1−xEuxTe$ quantum-dot superlattices is investigated as a function of PbSe dot layer thickness. An efficient lateral ordering and face centered cubic-like dot stacking occurs only for PbSe thicknesses between 4–6 monolayers. For smaller thicknesses, no correlations are formed, whereas for larger thicknesses the dots are vertically aligned along the growth direction. These transitions are explained by changes in interlayer dot interactions as a function of the dot size.