Effect of Coupled Quantum-Dot Insertion on the Radiative Recombination Probability of Wurtzite InGaN/GaN Quantum Dots

Light emission charactersitcs of single and coupled wurtzite (WZ) InGaN/GaN quantum-dot (QD) structures were investigated by using an effective mass theory. Strain components in the well of the coupled QD are found to be smaller than those in the well of the single QD structure. In particular, the reduction effect in ε_zz is dominant and, as a result, the polarization component I_zz for the strain tensor ε_zz is largely reduced for the coupled QD. The coupled QD structure shows much larger peak intensity than the single QD structure because the interband transition probability between electrons and holes is enhanced owing to the reduced internal field.