Annealing induced anisotropy in GaAs/AlGaAs quantum dots grown by droplet epitaxy

Adorno, Silvia; Bietti, Sergio; Sanguinetti, S.

doi:10.1016/j.jcrysgro.2012.11.006

Cited by 13 publications

(16 citation statements)

References 27 publications

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“…An elongation of the diameters is observed in the [110] direction with respect to the [110] direction. This elongation originates from the anisotropic diffusion of Ga atoms during the annealing step [46]. The variation in height is much stronger than the variation in diameter with increasing volume of Ga.…”

Section: Resultsmentioning

confidence: 97%

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Precise shape engineering of epitaxial quantum dots by growth kinetics

et al. 2015

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We show that independent size and morphology engineering of epitaxial quantum dots can be obtained using a kinetically controlled quantum dot fabrication procedure, namely droplet epitaxy. Due to the far-from-equilibrium droplet epitaxy procedure, which is based on the crystallization, under As flux, of a nanometric droplet of Ga, independent and precise tuning of quantum dot size, aspect ratio, and faceting can be achieved. The dependence of the dot morphology on the growth conditions is interpreted and described quantitatively through a model that takes into account the crystallization kinetics of the Ga stored in the droplet under As flux.

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Section: Resultsmentioning

confidence: 97%

“…A post-droplet-crystallization annealing procedure performed on sample V cap induces a slight change in the QD morphology related to thermally activated mass transport processes driven by the out-of-equilibrium state of DEQDs [46,65]. Overall, however, the QD morphology is maintained upon capping.…”

Section: Discussionmentioning

confidence: 99%

Precise shape engineering of epitaxial quantum dots by growth kinetics

et al. 2015

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“…In particular, we address the effect of Ga droplet arsenization for the formation of QDs at substrate temperature increased by about 300 • C with respect to previous reports [24] while avoiding QD elongation [25] due to anisotropy in Ga adatom diffusion [26][27][28]. We also address shape control issues, preserving hexagonal shape even at high temperatures, which has a strong impact on the optical quality and excitonic FSS.…”

Section: Introductionmentioning

confidence: 97%

High–temperature droplet epitaxy of symmetric GaAs/AlGaAs quantum dots

Bietti

Basset

Tuktamyshev

et al. 2020

Sci Rep

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We introduce a high-temperature droplet epitaxy procedure, based on the control of the arsenization dynamics of nanoscale droplets of liquid Ga on GaAs(111)A surfaces. The use of high temperatures for the self-assembly of droplet epitaxy quantum dots solves major issues related to material defects, introduced during the droplet epitaxy fabrication process, which limited its use for single and entangled photon sources for quantum photonics applications. We identify the region in the parameter space which allows quantum dots to self-assemble with the desired emission wavelength and highly symmetric shape while maintaining a high optical quality. The role of the growth parameters during the droplet arsenization is discussed and modelled.

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“…This step, while strongly improving the QD optical quality, 15 only slightly influences the dot shape, reducing the dot height and increasing the dot anisotropy. 16 The QDs were then covered with 4 nm Al 0.3 Ga 0.7 As layer grown by migration enhanced epitaxy. 17 A second annealing step was performed at 620 C and 6 Â 10 À6 Torr of As for 20 min to induce a selective mass redistribution at the top of the QDs.…”

Section: à2mentioning

confidence: 99%

Optical characterization of individual GaAs quantum dots grown with height control technique

Sarti

Muñoz‐Matutano

Bietti

et al. 2013

Journal of Applied Physics

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We show that the epitaxial growth of height-controlled GaAs quantum dots, leading to the reduction of the inhomogeneous emission bandwidth, produces individual nanostructures of peculiar morphology. Besides the height controlled quantum dots, we observe nanodisks formation. Exploiting time resolved and spatially resolved photoluminescence we establish the decoupling between quantum dots and nanodisks and demonstrate the high optical properties of the individual quantum dots, despite the processing steps needed for height control.

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Annealing induced anisotropy in GaAs/AlGaAs quantum dots grown by droplet epitaxy

Cited by 13 publications

References 27 publications

Precise shape engineering of epitaxial quantum dots by growth kinetics

Precise shape engineering of epitaxial quantum dots by growth kinetics

High–temperature droplet epitaxy of symmetric GaAs/AlGaAs quantum dots

Optical characterization of individual GaAs quantum dots grown with height control technique

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