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InAs self-assembled quantum dots (QDs) embedded within an InGaAs quantum well have been grown on InP substrate by low-pressure metalorganic vapor phase epitaxy. We find out that the underlying InGaAs layer could affect the dot growth dramatically in terms of size distribution and luminescence efficiency. After inserting a thin GaAs interface layer between the underlying InGaAs and the InAs QD layer, improved dot size uniformity and strong room temperature photoluminescence (PL) up to 2 μm were observed. In the case of InAs QDs with no GaAs layer, one has to reduce InAs QD layer thickness in order to obtain room temperature PL. These results suggest that InAs from the underlying InGaAs layer contribute to the InAs QD formation, and cause the InAs QDs to be non-uniform, but a thin GaAs interface layer could effectively block the migration of In atoms from the InGaAs layer toward InAs QDs, and therefore lead to more uniform QD formation with better luminescence efficiency. [Copyright &y& Elsevier]

Abstract High Entropy Alloys are inherently complex and span a vast composition space, making their research and discovery challenging. Developing quantitative predictions of their phase selection requires a large quantity of consistently determined experimental data. Here, we use combinatorial methods to fabricate and characterize 2478 quinary alloys based on Al and transition metals. All data are publicly available at http://materialsatlasproject.org/. Phase selection can be predicted for considered alloys when combining the content of FCC/BCC elements and the constituents' atomic size difference. Mining our data reveals that High Entropy Alloys with increasing atomic size difference prefer BCC structure over FCC. This preference is typically overshadowed by other selection motifs, which dominate during close-to-equilibrium processing. Not suggested by the Hume-Rothery rules, this preference originates from the ability of the BCC structure to accommodate a large atomic size difference with lower strain energy penalty which can be practically only realized in High Entropy Alloys. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]