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Analysis of institutional authors

Ulloa, J. M.Corresponding AuthorHierro, A.Author

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June 9, 2019
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Analysis of the modified optical properties and band structure of GaAs1-xSbx-capped InAs/GaAs quantum dots

Publicated to: JOURNAL OF APPLIED PHYSICS. 112 (7): 74311- - 2012-10-01 112(7), DOI: 10.1063/1.4755794

Authors:

Ulloa, J M; Llorens, J M; del Moral, M; Bozkurt, M; Koenraad, P M; Hierro, A
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Affiliations

Eindhoven Univ Technol, Dept Appl Phys, NL-5600 MB Eindhoven, Netherlands - Author
PTM, IMM Inst Microelect Madrid CNM CSIC, E-28760 Madrid, Spain - Author
Univ Politecn Madrid, Inst Syst Based Optoelect & Microtechnol ISOM, E-28040 Madrid, Spain - Author
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Abstract

The origin of the modified optical properties of InAs/GaAs quantum dots (QD) capped with a thin GaAs1-xSbx layer is analyzed in terms of the band structure. To do so, the size, shape, and composition of the QDs and capping layer are determined through cross-sectional scanning tunnelling microscopy and used as input parameters in an 8 x 8 k.p model. As the Sb content is increased, there are two competing effects determining carrier confinement and the oscillator strength: the increased QD height and reduced strain on one side and the reduced QD-capping layer valence band offset on the other. Nevertheless, the observed evolution of the photoluminescence (PL) intensity with Sb cannot be explained in terms of the oscillator strength between ground states, which decreases dramatically for Sb > 16%, where the band alignment becomes type II with the hole wavefunction localized outside the QD in the capping layer. Contrary to this behaviour, the PL intensity in the type II QDs is similar (at 15K) or even larger (at room temperature) than in the type 1 Sb-free reference QDs. This indicates that the PL efficiency is dominated by carrier dynamics, which is altered by the presence of the GaAsSb capping layer. In particular, the presence of Sb leads to an enhanced PL thermal stability. From the comparison between the activation energies for thermal quenching of the PL and the modelled band structure, the main carrier escape mechanisms are suggested. In standard GaAs-capped QDs, escape of both electrons and holes to the GaAs barrier is the main PL quenching mechanism. For small-moderate Sb (<16%) for which the type I band alignment is kept, electrons escape to the GaAs barrier and holes escape to the GaAsSb capping layer, where redistribution and retraping processes can take place. For Sb contents above 16% (type-II region), holes remain in the GaAsSb layer and the escape of electrons from the QD to the GaAs barrier is most likely the dominant PL quenching mechanism. This means that electrons and holes behave dynamically as uncorrelated pairs in both the type-I and type-II structures. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4755794]
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Keywords

Electronic-structureGaassbLayerScanning-tunneling-microscopyWavelength light-emission

Quality index

Bibliometric impact. Analysis of the contribution and dissemination channel

The work has been published in the journal JOURNAL OF APPLIED PHYSICS due to its progression and the good impact it has achieved in recent years, according to the agency WoS (JCR), it has become a reference in its field. In the year of publication of the work, 2012, it was in position 32/128, thus managing to position itself as a Q1 (Primer Cuartil), in the category Physics, Applied.

From a relative perspective, and based on the normalized impact indicator calculated from World Citations from Scopus Elsevier, it yields a value for the Field-Weighted Citation Impact from the Scopus agency: 1.11, which indicates that, compared to works in the same discipline and in the same year of publication, it ranks as a work cited above average. (source consulted: ESI Nov 13, 2025)

Specifically, and according to different indexing agencies, this work has accumulated citations as of 2026-04-25, the following number of citations:

  • WoS: 35
  • Scopus: 35
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Impact and social visibility

From the perspective of influence or social adoption, and based on metrics associated with mentions and interactions provided by agencies specializing in calculating the so-called "Alternative or Social Metrics," we can highlight as of 2026-04-25:

  • The use of this contribution in bookmarks, code forks, additions to favorite lists for recurrent reading, as well as general views, indicates that someone is using the publication as a basis for their current work. This may be a notable indicator of future more formal and academic citations. This claim is supported by the result of the "Capture" indicator, which yields a total of: 31 (PlumX).

It is essential to present evidence supporting full alignment with institutional principles and guidelines on Open Science and the Conservation and Dissemination of Intellectual Heritage. A clear example of this is:

  • Assignment of a Handle/URN as an identifier within the deposit in the Institutional Repository: https://oa.upm.es/16351/

As a result of the publication of the work in the institutional repository, statistical usage data has been obtained that reflects its impact. In terms of dissemination, we can state that, as of

  • Views: 538
  • Downloads: 690
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Leadership analysis of institutional authors

This work has been carried out with international collaboration, specifically with researchers from: Netherlands.

There is a significant leadership presence as some of the institution’s authors appear as the first or last signer, detailed as follows: First Author (ULLOA HERRERO, JOSE MARIA) and Last Author (HIERRO CANO, ADRIAN).

the author responsible for correspondence tasks has been ULLOA HERRERO, JOSE MARIA.

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Awards linked to the item

This work has been supported by the Comunidad de Madrid through the project Q&C Light (P2009/ESP-1503) and Nanophotonic devices for optical communications (CCG10-UPM/TIC-4932), by the European Union through the SANDiE Network of Excellence (Contract No. NMP4-CT-2004-500101), by STW-VICI Grant No. 6631 and by contracts TEC2008-06756-C03-01 and TEC2011-29120-C05-04. J. M. Ulloa would like to thank the support of the Spanish Ministerio de Ciencia e Innovacion through the Raman y Cajal program.
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