Microstructural and optical studies of multiply stacked CdSe/ZnSe quantum-dot structures with a large ZnSe spacer thickness

Transmission electron microscopy images showed that multiply stacked CdSe quantum-dot (QD) arrays with a large ZnSe spacer thickness were embedded in the ZnSe barriers. The temperature-dependence photoluminescence (PL) spectra showed that the peak corresponding to the interband transitions from the ground electronic subband to the ground heavy-hole band of the CdSe QDs shifted to a lower energy side with increasing temperature and that the PL linewidth at high temperature increased with increasing temperature. The activation energy of the electrons confined in the CdSe QDs was as large as 100 meV. The present observation can help improve understanding of the microstructural and optical properties in multiply stacked CdSe/ZnSe QDs.