Contactless electroreflectance study of CdSe/ZnBeSe quantum dots grown by molecular-beam epitaxy

Contactless electroreflectance was used to investigate the capped CdSe/ZnBeSe and CdSe/ZnSe quantum-dot (QD) structures grown by molecular beam epitaxy on GaAs [001] substrates. The features originating from the QDs transitions for the CdSe QDs sandwiched by ZnBeSe show blue shifts and narrower lineshape as compared to those grown on ZnSe. The blue shifts of the QD transitions are related to the smaller QD size and the slightly higher barrier energy due to the presence of Be, while the smaller broadening parameters indicate the higher uniformity of the QD size distribution of the ZnBeSe sample.