Effect of InGaAsSb capping layer on the structural properties of InAs/InGaAsSb quantum dots

The structural properties of the InAs QDs embedded in the InGaAsSb layers with varying In content of 3, 7, and 9 % have been investigated by x-ray diffraction. The In incorporation increases the in-plane and out-of-plane strain of the InGaAsSb in the structures. The density of crystalline defects is increased when the In content of 3 % is incorporated. However, the further increase of In content to 7 and 9 % leads to the decrease of the defect density as a result of the reduced lattice mismatch between the InAs QDs and InGaAsSb layers.