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

Abstract

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-ray diffraction (HRXRD) and low temperature photoluminescence spectroscopy (PL). The samples were grown by molecular beam epitaxy on GaAs(001) substrates. HRXRD revealed an enhanced stacking fault formation in quantum dot stacks increasing with decreasing spacer layer thickness. This could be suppressed by using strain compensating ZnSSe spacer layers. Strong electronic coupling of the quantum dots for spacer layers thinner than 5 nm was found by PL.