Optical and structural properties of CdSe/Zn(S)Se quantum dot stacks

Two-, three-. five-. and tenfold stacks of CdSe quantum dots embedded in a Zn(S)Se matrix have been systematically investigated by high resolution X-r ay diffraction (HRXRD) and low temperature photoluminescence spectroscopy ( PL). The samples were grown by molecular beam epitaxy on GaAs(001) substrat es. HRXRD revealed an enhanced stacking fault formation in quantum dot stac ks increasing with decreasing spacer layer thickness. This could be suppres sed by using strain compensating ZnSSe spacer layers. Strong electronic cou pling of the quantum dots for spacer layers thinner than 5 nm was found by PL.