Stabilization of PbSe quantum dots by ultrathin EuTe and SrTebarrier layers

Overgrowth of self-assembled quantum dots usually changes their shape and composition due to surface exchange reactions and redistribution of adatoms. As shown for PbSe dots, this can be completely suppressed by covering the dots with ultrathin EuTe or SrTe barrier layers, based on the large EuTe and SrTe binding energies. The model is supported by annealing experiments that show that these barrier layers also suppress the usual coarsening and Ostwald ripening process.