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A detailed theoretical study of optical and structural properties of heterogeneously coupled Stranski-Krastanov (SK) on submonolayer (SML) QDs heterostructure with In0.18Ga0.82AsYSb1-Y capping on InAs SK QD has been done using Nextnano++ software. Variation of Sb composition was taken as 10, 15, 20 and 25%. By solving 3-D Schrodinger’s equation the biaxial and hydrostatic strain distribution, energy band diagram and PL peak observation is done. It has been noted that increasing Sb composition contributes in transition from type I to type II. This transition can be discovered in positions of probability density function for electron and holes and from energy band illustrations. The biaxial strain is responsible for energy splitting in light hole (LH) and heavy hole (HH) and its distribution in SK QD increases with increasing Sb composition. The hydrostatic strain is compressive strain in nature, which is responsible for carrier confinement in conduction band. With increasing Sb composition the magnitude of hydrostatic strain is observed as diminishing. From the ground state energy levels of electron-hole Eigen state (E1-H1) PL emission wavelength have been observed for all the four structures. It has been noted that higher the composition of Sb, higher the wavelength emission. In overall analysis it has been observed that type-II has lower compressive strain inside the QDs and higher wavelength emission. The composition selection demonstrates both type-I and type-II energy band profile which can be advantageous in many optoelectronic device properties. This theoretical study can be useful in optimization of strain coupled heterostructures for better crystalline quality.
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