Stability of InAs quantum dots

We monitor the postgrowth desorption of self-assembled InAs quantum dots with electron diffraction. A kinetic model is presented that quantitatively describes the temperature and arsenic pressure dependence of the postgrowth dot lifetimes. The central findings establish the stabilization of the InAs quantum dots by an arsenic flux, the importance of the precursor state for the impinging arsenic molecules, and layer-by-layer desorption starting from the dot-top. In a second step the model results are employed to refine the description of the growth process providing a now complete picture of the here relevant desorption mechanisms. The such calculated sticking coefficient matches quantitatively our temperature-dependent measurements of the critical time up to quantum dot formation.