CDSE ZNSE QUANTUM-DOT STRUCTURES - STRUCTURAL AND OPTICAL INVESTIGATIONS/

Using migration enhanced epitaxy the self-organized formation of CdSe islands on ZnSe in open and overgrown structures has been studied by t ransmission electron microscopy, high-resolution X-ray diffraction, at omic force microscopy, photoluminescence and excitation spectroscopy. The transition from homogeneous CdSe quantum wells with flat interface s to fluctuating CdSe films could be observed when exceeding the criti cal thickness. These interrupted layers contain CdSe quantum dots embe dded in Cd1-xZnxSe with a concentration gradient. Islands observed on open structures are unstable in time. Their chemical nature is still u nclear due to the fact that similar features are obtained on pure ZnSe . First results on other highly lattice mismatched II-VI systems like CdTe/ZnSe and ZnTe/ZnSe will he presented.