Single and stacked sheets of CdSe quantum islands, embedded in a ZnSSe matrix, were grown by metalorganic vapor-phase epitaxy on GaAs homoepitaxial buffers to induce a narrow size distribution of the quantum island ensemble. The insertion of a GaAs buffer leads to a distinctly smoother II-VI/III-V interface. The full-width at half-maximum of the CdSe-related localized excitonic emission is found to be reduced for structures grown on a GaAs buffer proving the success of this approach. GaAs buffers grown in the same reactor prior to TT-VI epitaxy lead to slightly better results than buffers grown in a separate reactor.