Emission and strain in InGaAs/GaAs structures with embedded InAs quantum dots

The photoluminescence (PL) and X ray diffraction (XRD) have been studied in the GaAs/InxGa1-xAs/In0.15Ga0.85 As/GaAs quantum wells with embedded InAs quantum dots (QDs) in dependence on the composition of the capping InxGa1-xAs layers. The parameter x in capping InxGa1-xAs layers varied from the range 0.10-0.25. In concentration (x) increasing in capping layers is accompanied by the variation non-monotonously of InAs QD emission: the PL intensity and peak positions. To understand the reasons of emission variation, the PL temperature dependences and XRD have been investigated in strained QD structures. It was revealed that the process of Ga/In inter diffusion at the InxGa1-xAs/InAs QD interface and the level of elastic deformation are characterized by the dependence non monotonous versus parameter x in capping InxGa1-xAs layers. The physical reasons of the variation no monotonously of elastic strains in studied structures have been discussed.