Formation of self-organized CdSe quantum dots on ZnSe 100/ surfaces by molecular beam epitaxy

We have investigated the formation of self-organized CdSe quantum dots QDs.on ZnSe 100.surfaces with the use of photoluminescence PL. and transmission electron microscopy TEM.. TEM measurement reveals that CdSe grows two-dimensionally on ZnSe 100. surfaces in the initial stages, and then at around 1.8 monolayer ML., CdSe grows three-dimensionally and begins to nucleate QDs. Coherent CdSe QDs are naturally formed on ZnSe surfaces, when the thickness of CdSe layers is about 2 ML. The plan-view TEM images reveal that CdSe QDs have a relatively narrow distribution of QD size, and that the density and diameter of CdSe QDs are about 1010 cmy2 and 30 nm, respectively. Moreover, CdSe QDs exhibit a strong green emission even at room temperature. q2000 Elsevier Science B.V. All rights reserved