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arXiv · 1905.05303

Bismuth-surfactant-induced growth and structure of InAs/GaAs(110) quantum dots

Ryan B. Lewis·Achim Trampert·Esperanza Luna·Jesús Herranz·Carsten Pfüller·Lutz Geelhaar
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Abstract

We explore the Bi-surfactant-directed self-assembly and structure of InAs quantum dots grown on GaAs(110) by molecular beam epitaxy. The addition of a Bi flux during InAs deposition changes the InAs growth mode from two-dimensional (2D) Frank-van der Merwe to Stranski-Krastanov, resulting in the formation of three-dimensional (3D) InAs islands on the surface. Furthermore, exposing static InAs 2D layers to Bi induces a rearrangement of the strained layer into 3D islands. We explore the effect of varying the InAs thickness and Bi flux for these two growth approaches, observing a critical thickness for 3D island formation in both cases. Characterization of (110) InAs quantum dots with high-resolution transmission electron microscopy reveals that larger islands grown by the Stranski-Krastanov mode are plastically relaxed, while small islands grown by the on-demand approach are coherent. Strain relaxation along the [1-10] direction is achieved by 90 degree pure-edge dislocations with dislocation lines running along [001]. In contrast, strain relief along [001] is by 60 degree misfit dislocations. This behaviour is consistent with observations of planar (In,Ga)As/GaAs(110) layers. These results illustrate how surfactant Bi can provoke and control quantum dot formation where it normally does not occur.

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Ryan B. Lewis, Achim Trampert, Esperanza Luna, Jesús Herranz, Carsten Pfüller, Lutz Geelhaar. 2019-05-13. Bismuth-surfactant-induced growth and structure of InAs/GaAs(110) quantum dots. https://doi.org/10.1088/1361-6641%2Fab3c23

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