HR XRD and emission of In_xGa_1-xAs/GaAs quantum wells with embedded InAs quantum dots at the variation of In_xGa _1-xAs composition

The high resolution X ray diffraction (HR-XRD) diagrams have been studied in the GaAs/In_xGa_1-xAs /In_0.15Ga _0.85As/GaAs quantum wells with embedded InAs quantum dots (QDs) in dependence on the composition of the capping In_xGa_1-xAs layers. The parameter x in capping In_xGa_1-xAs layers varied from the range 0.10-0.25. These technological changes have been accompanied by the variation non-monotonously of InAs QD emission. Numerical simulation of HR-XRD results has shown that the level of elastic strains and the composition of quantum layers vary none monotonously in studied QD structures. Simultaneously it was revealed that the process of Ga/In inter diffusion at the In_xGa_1-xAs/InAs QD interface are characterized by the dependence non monotonous versus parameter x in capping In_xGa _1-xAs layers. The physical reasons of the mentioned optical and structural effects in studied structures have been discussed.