Advantages of using CdS as Cd-source for growth of CdSe quantum islands and wells

In this study we report on the fabrication and investigation of high qualit y CdSe-based quantum structures embedded in ZnSe. The structures were grown by molecular beam epitaxy using a novel growth technique in which the comm only used Cd-elemental source is substituted by a CdS compound source. An e xchange reaction between the sulfur and elemental Se leads to the growth of CdSe with a minor sulfur contamination of the order of 1% depending on the growth conditions. Quantum structures grown with the compound show a bette r homogeneity and narrower photoluminescence linewidth than conventionally grown structures even though high resolution transmission electron microsco py indicates that intermixing of CdSe and ZnSe still occurs. The properties and implications of the structures grown by the new method will be discuss ed.