Enhancement of the activation energy due to coupling effects in CdxZn1-xTe/ZnTe double quantum dots

Abstract

Temperature-dependent photoluminescence measurements show that the activation energy of Cd0.6Zn0.4Te/ZnTe double quantum dots (QDs) increases with decreasing ZnTe separation layer. At a separation-layer thickness of 6 nm, this behavior can be attributed to enhancement in the tunneling probability of carriers from the smaller Cd0.6Zn0.4Te 1.5-monolayer (ML) QDs to the larger 3.0-ML QDs due to the coupling effect between the upper and the lower Cd0.6Zn0.4Te QDs. The present results indicate that the activation energy in Cd0.6Zn0.4Te/ZnTe double QDs is significantly affected by the ZnTe separation layer.