InAs island-induced-strain driven adatom migration during GaAs overlayer growth

Xie, Qiwei; Chen, P.; Madhukar, A.

doi:10.1063/1.112790

Cited by 201 publications

(79 citation statements)

References 9 publications

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“…This can be explained by the difference in mobility of Al and Ga atoms; the Ga atoms are more mobile and will migrate along the side of the QD during capping while the Al atoms, which are less mobile, are more likely to remain on top of the QD. The driving force behind the migration of the incoming adatoms away from the top of the QD is the convex curvature of the growth front at the position of the QDs [18]. Note that this different from the SK-grown QDs of the previous sections were strain induced by the lattice mismatch is the driving process.…”

Section: Droplet Epitaxymentioning

confidence: 92%

Shape control of quantum dots studied by cross-sectional scanning tunneling microscopy

Keizer

Bozkurt

Bocquel

et al. 2011

Journal of Applied Physics

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In this cross-sectional scanning tunneling microscopy study we investigated various techniques to control the shape of self-assembled quantum dots (QDs) and wetting layers (WLs). The result shows that application of an indium flush during the growth of strained InGaAs/GaAs QD layers results in flattened QDs and a reduced WL. The height of the QDs and WLs could be controlled by varying the thickness of the first capping layer. Concerning the technique of antimony capping we show that the surfactant properties of Sb result in the preservation of the shape of strained InAs/InP QDs during overgrowth. This could be achieved by both a growth interrupt under Sb flux and capping with a thin GaAsSb layer prior to overgrowth of the uncapped QDs. The technique of droplet epitaxy was investigated by a structural analysis of strain free GaAs/AlGaAs QDs. We show that the QDs have a Gaussian shape, that the WL is less than 1 bilayer thick, and that minor intermixing of Al with the QDs takes place.

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Section: Droplet Epitaxymentioning

confidence: 92%

Shape control of quantum dots studied by cross-sectional scanning tunneling microscopy

Keizer

Bozkurt

Bocquel

et al. 2011

Journal of Applied Physics

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“…One possible explanation would be that the presence of Sb "freezes" the growth front reducing the mobility of the Ga adatoms, which are forced to stay where they arrive. For that reason, and contrary to what happens with other materials, 22 the capping layer would directly grow on top of the QDs from the beginning, protecting them from intermixing and segregation, the two main factors causing QD decomposition. This explanation is in agreement with the fact that no composition modulation is observed in the GaAsSb capping layer despite the high miscibility gap ͑as described before͒, indicating that no adatom migration takes place in the presence of Sb.…”

Section: -2mentioning

confidence: 97%

Effect of a lattice-matched GaAsSb capping layer on the structural properties of InAs/InGaAs/InP quantum dots

Ulloa¹,

Koenraad²,

Bonnet-Eymard³

et al. 2010

Journal of Applied Physics

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. The influence of a lattice-matched GaAsSb capping layer on the structural properties of self-assembled InAs quantum dots ͑QDs͒ grown on InP substrates is studied on the atomic scale by cross-sectional scanning tunneling microscopy. While lattice-matched In 0.53 Ga 0.47 As-capped QDs are clearly truncated pyramids, GaAs 0.51 Sb 0.49 -capped QDs grown under the same conditions look like full pyramids and exhibit a larger height, indicating that capping with GaAsSb reduces dot decomposition. Since there are no differences in strain between the two capping layers, this behavior is most likely related to the surfactant effect of Sb, which stabilizes the growth front and avoids adatom migration.

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“…When GaAs is grown on InAs islands, GaAs does not prefer to grow on the islands. 11,12 Therefore, the top of an island is not covered with a thin GaAs layer. During interruption after GaAs-layer growth, In atoms detach from the top of the island to become adatoms, and they migrate to form a partial WL on GaAs ͑Fig.…”

Section: Discussionmentioning

confidence: 99%

Size, density, and shape of InAs quantum dots in closely stacked multilayers grown by the Stranski–Krastanow mode

Shiramine¹,

Muto²,

Shibayama³

et al. 2003

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Closely stacked multilayer structures of InAs islands with intermediate-layer thicknesses d of 3, 6, 10, and 20 nm were grown by the Stranski-Krastanow mode of molecular beam epitaxy and were observed using transmission electron microscopy ͑TEM͒ and atomic force microscopy ͑AFM͒. The multilayers consisted of five InAs layers each of a thickness of 1.8 monolayers and four GaAs layers each of a thickness d. Columns of coherent islands were observed by cross-sectional TEM. Changes in the size and density of the islands with d, determined by AFM, could be explained in terms of ͑i͒ change in the vertical pairing probability of islands, ͑ii͒ detachment of In from the top of the island, and ͑iii͒ surface segregation of In. The observed AFM images of the islands were elliptical. Their major axis was in the ͓110͔ direction, and the length of the minor axis was 80% of that of the major axis.

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InAs island-induced-strain driven adatom migration during GaAs overlayer growth

Cited by 201 publications

References 9 publications

Shape control of quantum dots studied by cross-sectional scanning tunneling microscopy

Shape control of quantum dots studied by cross-sectional scanning tunneling microscopy

Effect of a lattice-matched GaAsSb capping layer on the structural properties of InAs/InGaAs/InP quantum dots

Size, density, and shape of InAs quantum dots in closely stacked multilayers grown by the Stranski–Krastanow mode

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