Self-organized CdSe/ZnSe quantum dots on a ZnSe (1 1 1)A surface

Self-organized CdSe quantum dots (SQDs) were grown by atomic layer epitaxy (ALE). As a buffer layer we used the nearly atomically flat surface of thin (1 1 1)A ZnSe layers grown on (1 1 1)A GaAs. In this special system we find, due to the enhanced surface diffusion, formation of coherently strained islands (coherent Stranski-Krastanow islanding) already well below the critical thickness ( ∼ 3 monolayers) of CdSe on ZnSe. An increase in the material deposition leads to an increase in the density of the dots rather than a change in average base diameter (47 ± 5 nm). The strongly blue shifted emission energy of typically 2.3 eV corresponds to an ZnCdSe alloy with approximately 50% of Zn. Micro-Auger measurements were used to determine the wetting layer thickness.