Single layer and stacked CdSe self-assembled quantum dots with ZnCdMgSe barriers for visible and white light emitters

Abstract

We have grown structures with single layers of self-assembled quantum dots (SAQDs) and stacked layers of SAQDs in the II-VI materials systems CdSe∕ZnCdMgSe. The structures were grown on InP substrates by molecular beam epitaxy. Good control of the quantum dot (QD) size by controlling the CdSe deposition time was obtained, giving structures whose emission can be adjusted to be at any wavelength within the visible spectrum range. Stacked QD structures consisting of three QD layers emitting in the red, green and blue (R-G-B) regions of the spectrum, respectively, were grown. Photoluminescence measurements exhibited bright white emission that could be observed by eye, at 77K or at room temperature, as a result of the mixing of the three lines. These results indicate that this material may be an attractive alternative for optical applications in the R-G-B range and may be useful for the fabrication of white light sources.