SELF-ORGANIZED CDSE ZNSE QUANTUM DOTS ON A ZNSE(111)A SURFACE/

Self-organized CdSe quantum dots (SQDs) were grown by atomic layer epi taxy (ALE). As a buffer layer we used the nearly atomically flat surfa ce of thin (1 1 1)A ZnSe layers grown on (1 1 1)A GaAs. In this specia l system we find, due to the enhanced surface diffusion, formation of coherently strained islands (coherent Stranski-Krastanow islanding) al ready well below the critical thickness ( similar to 3 monolayers) of CdSe on ZnSe. An increase in the material deposition leads to an incre ase in the density of the dots rather than a change in average base di ameter (47 +/- 5 nm). The strongly blue shifted emission energy of typ ically 2.3 eV corresponds to an ZnCdSe alloy with approximately 50% of Zn. Micro-Auger measurements were used to determine the wetting layer thickness. (C) 1998 Elsevier Science B.V. All rights reserved.