Strain distributions and interband transitions of Cd_x Zn1-x Te/ZnTe asymmetric double quantum dots with different degree of coupling

Strain distributions and interband transitions of Cd_xZn _1-xTe/ZnTe asymmetric double quantum dots (DQDs) with different degree of coupling were calculated by using a three-dimensional finite difference method (FDM) taking into account strain and nonparabolicity effects. Bird's-eye views of the truncated contour plots of the ground state wave functions at the conduction band of the Cd_0.6Zn_0.4Te/ZnTe DQDs showed the transition behavior from the coupling to the decoupling behaviors with increasing ZnTe spacer layer thickness. The interband transition energies from the ground electronic subband to the ground heavy-hole band (E₁ -HH₁) in the Cd_xZn_1-xTe/ZnTe DQDs, as determined from the FDM calculations, were in reasonable agreement with the experimental peaks of the temperature-dependent photoluminescence spectra corresponding to the (E₁ -HH₁) interband transition energies in the temperature range from 32 to 130 K.