FORMATION OF SELF-ASSEMBLING CDSE QUANTUM DOTS ON ZNSE BY MOLECULAR-BEAM EPITAXY

We report the formation of self-assembling CdSe quantum dots during mo lecular beam epitaxial growth on ZnSe and ZnMnSe. Atomic force microsc opy measurements on specimens with uncapped dots show relatively narro w dot size distributions, with typical dot diameters of 40+/-5 nm, and with a diameter-to-height ratio consistently very close to 4:1. Uncap ped CdSe dots are unstable with time: their density was observed to dr op by an order of magnitude in 10 days, with clear evidence of ripenin g observed for some dots. Photoluminescence from capped dots indicates exciton localization much stronger than in ZnCdSe/ZnSe quantum wells, due to the additional lateral confinement. (C) 1996 American Institut e of Physics.