Atomic scale study of the impact of the strain and composition of the capping layer on the formation of InAs quantum dots

Ulloa, JM José Maria; Çelebi, Cem; Koenraad, PM Paul; Simon, Adèle; Gapihan, E.; Létoublon, Antoine; Bertru, Nicolas; Drouzas, I.; Mowbray, D. J.; Steer, M. J.; Hopkinson, M.

doi:10.1063/1.2722738

Cited by 51 publications

(44 citation statements)

References 35 publications

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“…For instance, the tuning of the composition of the capping layer makes it possible to control the strain field inside the QDs 11 and the QDs erosion process. 12 This means that in order to control the structural properties of the nanostructures, strain engineering during capping is just as important as during the formation of the QDs. In this letter, we use a Kinetic Monte Carlo (KMC) model 13 to investigate the role of the strain in the control of the morphology of the QDs during capping.…”

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confidence: 99%

Height control of self-assembled quantum dots by strain engineering during capping

Grossi

Smereka

Keizer

et al. 2014

Applied Physics Letters

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Strain engineering during the capping of III-V quantum dots has been explored as a means to control the height of strained self-assembled quantum dots. Results of Kinetic Monte Carlo simulations are confronted with cross-sectional Scanning Tunnel Microscopy (STM) measurements performed on InAs quantum dots grown by molecular beam epitaxy. We studied InAs quantum dots that are capped by InxGa(1−x)As layers of different indium compositions. Both from our realistic 3D kinetic Monte Carlo simulations and the X-STM measurements on real samples, a trend in the height of the capped quantum dot is found as a function of the lattice mismatch between the quantum dot material and the capping layer. Results obtained on additional material combinations show a generic role of the elastic energy in the control of the quantum dot morphology by strain engineering during capping.

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confidence: 99%

Height control of self-assembled quantum dots by strain engineering during capping

Grossi

Smereka

Keizer

et al. 2014

Applied Physics Letters

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“…Such a modified strain difference between the QD and SRL can also induce differences in the island size. 39 In fact the observed heights of the QDs are as much as twice compared with QDs capped with pure GaAs. Ripalda et al 40 reported the use of GaAsSb capping to extend the emission wavelength of InGaAs quantum dot structures and observed that a type II alignment takes place when the Sb content of the capping layer is higher than 14%.…”

Section: Role Of Segregation In Inas/gaas Quantum Dot Structures Cappmentioning

confidence: 79%

Role of segregation in InAs/GaAs quantum dot structures capped with a GaAsSb strain-reduction layer

et al. 2009

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Please check the document version of this publication:• A submitted manuscript is the 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.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement: We report a combined experimental and theoretical analysis of Sb and In segregation during the epitaxial growth of InAs self-assembled quantum dot structures covered with a GaSbAs strain-reducing capping layer. Cross-sectional scanning tunneling microscopy shows strong Sb and In segregation which extends through the GaAsSb and into the GaAs matrix. We compare various existing models used to describe the exchange of group III and V atoms in semiconductors and conclude that commonly used methods that only consider segregation between two adjacent monolayers are insufficient to describe the experimental observations. We show that a three-layer model originally proposed for the SiGe system ͓D. J. Godbey and M. G. Ancona, J. Vac. Sci. Technol. A 15, 976 ͑1997͔͒ is instead capable of correctly describing the extended diffusion of both In and Sb atoms. Using atomistic modeling, we present strain maps of the quantum dot structures that show the propagation of the strain into the GaAs region is strongly affected by the shape and composition of the strain-reduction layer.

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“…2). Indeed, material composition of GaAs-capped QDs significantly change in a growth process due to Ga/In interdiffusion, while compositional intermixing can be considerably suppressed in InGaAs-capped QDs [11,13]. Temperature-dependent PR and PL spectra for as-grown L444 and L442 structures in the photon energy region of QD and QW optical transitions are presented in Fig.…”

Section: Spectroscopic Results and Discussionmentioning

confidence: 99%

“…This significant energy shift could be explained in terms of reducing strain, suppressing compositional mixing and increasing dot height [11][12][13].…”

Section: Spectroscopic Results and Discussionmentioning

confidence: 99%

Temperature-dependent modulated reflectance and photoluminescence of InAs–GaAs and InAs–InGaAs–GaAs quantum dot heterostructures

et al. 2016

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Optical transitions and electronic properties of epitaxial InAs quantum dots (QDs) grown with and without InGaAs strain-relieving capping layer within GaAs/AlAs quantum well (QW) are investigated. Modulated reflectance and photoluminescence (PL) spectroscopy is used to probe the QD-and QW-related interband optical transitions over the temperature range of 3-300 K. The observed spectral features in QDs are identified using numerical calculations in a framework of 8-band k · p method. It is found that covering the dots by a 5 nm-thick InGaAs layer yields the energy red-shift of ground-state transition by ∼ 150 meV. Moreover, the analysis of interband transition energy dependence on temperature using Varshni expression shows that material composition of InAs QDs significantly changes due to Ga/In interdiffusion. A comparison of emission-and absorption-type spectroscopy applied for InAs-GaAs QDs indicates a Stokes shift of ∼ 0.02 meV above 150 K temperature.

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Atomic scale study of the impact of the strain and composition of the capping layer on the formation of InAs quantum dots

Cited by 51 publications

References 35 publications

Height control of self-assembled quantum dots by strain engineering during capping

Height control of self-assembled quantum dots by strain engineering during capping

Role of segregation in InAs/GaAs quantum dot structures capped with a GaAsSb strain-reduction layer

Temperature-dependent modulated reflectance and photoluminescence of InAs–GaAs and InAs–InGaAs–GaAs quantum dot heterostructures

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