GaAs/InGaAs heterostructure strain effects on self-assembly of InAs quantum dots Article uri icon

abstract

  • In this study, the quantum dots (QDs) self-assembly properties were affected by strain modulation. The strain of the GaAs (100) surface was modulated prior to the growth of InAs with the aim to tailor the size and distribution of self-assembled QDs. Changes in the strain fields were achieved with the buried GaAs/InGaAs heterostructure by varying the GaAs layer thickness Σ, which significantly influences several parameters collectively involved in the QDs self-assembly process. In situ characterization of the heterostructure shows that the InAs/GaAs critical thickness and the surface diffusion parameter, the latter of which is an indicative of the QDs density, decreased with Σ. High-resolution X-ray diffraction measurements confirmed that depending on Σ, the InGaAs layer can be partially relaxed, presumably through the introduction of dislocations that are advanced by the QDs strain. Numerical simulations of the heterostructures were performed, with the sample%27s geometry and other properties obtained from its experimental characterization as input data. The results confirmed variations in strain resulting from changes in the GaAs/InGaAs heterostructure. These findings contribute to the understanding of strain distribution and can thus lead to improvements in the self-assembly properties of InAs QDs. © 2020 Elsevier B.V.
  • In this study, the quantum dots (QDs) self-assembly properties were affected by strain modulation. The strain of the GaAs (100) surface was modulated prior to the growth of InAs with the aim to tailor the size and distribution of self-assembled QDs. Changes in the strain fields were achieved with the buried GaAs/InGaAs heterostructure by varying the GaAs layer thickness Σ, which significantly influences several parameters collectively involved in the QDs self-assembly process. In situ characterization of the heterostructure shows that the InAs/GaAs critical thickness and the surface diffusion parameter, the latter of which is an indicative of the QDs density, decreased with Σ. High-resolution X-ray diffraction measurements confirmed that depending on Σ, the InGaAs layer can be partially relaxed, presumably through the introduction of dislocations that are advanced by the QDs strain. Numerical simulations of the heterostructures were performed, with the sample's geometry and other properties obtained from its experimental characterization as input data. The results confirmed variations in strain resulting from changes in the GaAs/InGaAs heterostructure. These findings contribute to the understanding of strain distribution and can thus lead to improvements in the self-assembly properties of InAs QDs. © 2020 Elsevier B.V.

publication date

  • 2020-01-01