Controlling the size and density of self-assembled PbSe quantum dots by adjusting the substrate temperature and layer thickness

The formation of self-assembled PbSe quantum dots by molecular-beam epitaxy of PbSe on PbTe (111) is investigated in dependence of growth temperature and layer thickness. It is shown that in the temperature range of $\text{240\hspace{0.05em}°}\mathrm{C}$ to $\text{420\hspace{0.05em}°}\mathrm{C},$ the dot density and dot height vary exponentially with temperature, whereas the wetting layer thickness and the dot shapes remain essentially constant. A different behavior is observed for the dependence on the PbSe thickness, which linearly changes the average dot height but only slightly affects the dot density. Both parameters allow an efficient control of the quantum dot sizes as is essential for device applications.