Surface segregation of In atoms during molecular beam epitaxy and its influence on the energy levels in InGaAs/GaAs quantum wells

Muraki, K.; Fukatsu, S.; Shiraki, Y.; Ito, Ryoichi

doi:10.1063/1.107835

Cited by 474 publications

(346 citation statements)

References 7 publications

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“…The strain effect is included via deformation potential theory. 32 i>-wit>-(^> (26) We want to point out that it is generally known that the k' p method has some problems associated with it when applied to calculations involving nanostructures.…”

Section: < 19 >mentioning

confidence: 99%

“…26 The eight-band k-p method represents an extension of the Luttinger-Kohn formalism, which describes coupling among the light-hole, heavy-hole and split-off valence bands to second order in k, but is modified to include the linear coupling between the conduction and valence band states. This is necessary in order to correctly model conduction band non-parabolicity.…”

Section: Electronic Structure and Optical Transitionsmentioning

confidence: 99%

See 1 more Smart Citation

Self-assembled (In,Ga)As/GaAs quantum-dot nanostructures: strain distribution and electronic structure

Stoleru

Pal

Towe

2002

Physica E: Low-dimensional Systems and Nanostructures

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Section: < 19 >mentioning

confidence: 99%

Section: Electronic Structure and Optical Transitionsmentioning

confidence: 99%

Self-assembled (In,Ga)As/GaAs quantum-dot nanostructures: strain distribution and electronic structure

Stoleru

Pal

Towe

2002

Physica E: Low-dimensional Systems and Nanostructures

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“…Muraki et al 70 presented a simple exchange model for InGaAs/GaAs QWs. According to this model the In ͑cation͒ concentration in the nth monolayer can be expressed in the form…”

Section: Segregation In Epitaxial Layersmentioning

confidence: 99%

“…The previous models of segregation are based on the twostate exchange 70,71,73 mechanism, where only atomic exchange among the subsurface and surface states is considered. Godbey and Ancona 75 instead proposed to extend the kinetic model to a three-layer exchange mechanism.…”

Section: ͑6͒mentioning

confidence: 99%

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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“…By modelling the indium segregation, the outward displacement of the segregated WL can be calculated by integration of the analytical expression derived by Davies for the outward displacement of a cleaved quantum well [24]. Several models for indium segregation have been proposed [30][31][32][33]. We use the phenomenological model of Muraki et al [31], which has been shown to describe well the indium composition x(n) of InAs WLs [28]:…”

Section: Formation Of the Wetting Layermentioning

confidence: 99%

InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

Ulloa

Offermans

Koenraad

2008

Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics

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Introduction Quantum dot formationSelf-assembled quantum dots (QDs) have attracted much attention in the last years [1,2]. These nanostructures are very interesting from a scientific point of view because they form nearly ideal zero-dimensional systems in which quantum confinement effects become very important. These unique properties also make them very interesting from a technological point of view. For example, InAs QDs are employed in QD lasers [3,4], single electron transistors [5], midinfrared detectors [6,7], single-photon sources [8,9], etc. InAs QDs are commonly created by the Stranski-Krastanov growth mode when InAs is deposited on a substrate with a bigger lattice constant, like GaAs or InP [10]. Above a certain critical thickness of InAs, three-dimensional islands are spontaneously formed on top of a wetting layer (WL) to reduce the strain energy. Once created, the QDs are subsequently capped, a step which is required for any device application.For any application based on InAs QDs, an accurate control of their electronic properties is required. The electron and hole states in the dot are very sensitive to the QD size, shape and composition (as well as to the surrounding material), and therefore an accurate control of the QD structural properties is necessary for applications. This explains the strong effort dedicated in the last years to the structural characterization of QDs [11], which is essential in order to have a deep understanding of the QD formation process. Although a lot of effort has been dedicated to study surface QDs, there are relatively few studies focused on the effect of the capping process [12][13][14][15][16][17][18][19][20]. Some of these studies have already shown significant differences in size, shape and composition between uncapped and capped QDs. For example, an important collapse of the QD height has been reported for InAs/GaAs QDs capped with GaAs [14,15,[17][18][19], revealing the big influence of the capping process on the structural properties of the QDs. Indeed, critical issues affecting the dot take place during capping like dot decomposition, intermixing, segregation, As/P exchange and composition modulation in the capping layer. This means that the real buried QDs must be studied in order to understand the complete QD formation process. Cross-sectional scanning tunnelling microscopy is an especially useful technique for this purpose, because it allows the structure of the capped dots at the atomic scale to be assessed. Cross-sectional scanning tunnelling microscopy (X-STM)The scanning tunnelling microscope is part of the family of scanning probe microscopes, which are able to provide direct real space information of a physical property at the atomic scale. This

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Surface segregation of In atoms during molecular beam epitaxy and its influence on the energy levels in InGaAs/GaAs quantum wells

Cited by 474 publications

References 7 publications

Self-assembled (In,Ga)As/GaAs quantum-dot nanostructures: strain distribution and electronic structure

Self-assembled (In,Ga)As/GaAs quantum-dot nanostructures: strain distribution and electronic structure

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

InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

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