Optical and morphological properties of self-assembled InAs quantum dots (QDs) covered by InxGa1-xAs strain reducing layers (SRL) with different thicknesses (2. 4, 6 and Snm) and compositions (x-0.13, 0.1.8 and 0.30) were investigated. Photolumincscencc from InAs QDs shows the dependence on indium mole fraction and thickness of the overgrown InxGa 1-xAs SRL. Improvement in PL intensity and narrowing of PL width up to 26 meV occurred together with a red shift of up to 138 nm when the QDs were coved with 6 nm of In0.18Ga0.82As. Also, we found that when the total amount of InAs deposited to form the QDs and the SRL was larger than a critical value of around 6MLs, the surface roughness increased and the PL intensity decreased drastically.
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