Island shape instabilities and surfactant-like effects in the growth of InGaAs/GaAs quantum dots

R. Leon*, C. Lobo, X. Z. Liao, J. Zou, D. J.H. Cockayne, S. Fafard

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    10 Citations (Scopus)

    Abstract

    InGaAs/GaAs island formation during vapor phase epitaxy showed diverging behaviors when varying group V partial pressures (PP). Differences include changes in critical thicknesses for the onset of the Stranski-Krastanow (S-K) transformation, surface coverages, ratios between coherent and incoherent islands, and dissimilar morphologies upon annealing. These results show that slightly different values for the 2D-3D transition can also be obtained in InGaAs/GaAs depending on AsH3 PP. Photoluminescence spectroscopy of capped islands showed that the wetting layer thickness does not change beyond the onset of the S-K transformation for conditions producing stable islands. Annealing experiments done at high AsH3 PP show Ostwald ripening, but we also observe that small, high density, lens-shaped islands are unaffected by prolonged annealing and do not ripen when an `optimum' low AsH3 PP is used during the island growth and in-situ annealing. The later experiments show that small lens shaped islands can be found in equilibrium if InGaAs surface energies are minimized. These findings lead to the conclusion that AsH3 can raise surface energies acting as an impurity-free `morphactant' in InGaAs growth.

    Original languageEnglish
    Pages (from-to)40-45
    Number of pages6
    JournalThin Solid Films
    Volume357
    Issue number1
    DOIs
    Publication statusPublished - 1 Dec 1999

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