Influence of znte separation layer thickness on optical properties in cdte/znte asymmetric double quantum dots

We investigate the influence of ZnTe separation layer thickness on optical properties in CdTe/ZnTe asymmetric double quantum dots (QDs). Photoluminescence spectra show that the excitonic peak corresponding to transitions from the ground electronic subband to the ground heavy-hole band in 4.5 monolayer (ML) CdTe/ZnTe QDs (LQDs) shifts to lower energies with decreasing separation layer thickness, owing to an increase in the size of the QDs resulting from intermixing caused by strain from the 3.0 ML CdTe/ZnTe QDs (SQDs). The peak intensity of the LQDs with respect to the intensity of the SQDs for the asymmetric double QD structures increases with decreasing ZnTe separation layer thickness. This behavior is attributed to an increase in the carriers in the LQDs due to the tunneling of carriers from the SQDs to the LQDs through a thin separation layer.