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Analysis of institutional authors

Fernando-Saavedra, A.Corresponding AuthorSanchez-Garcia, M. A.AuthorCalleja, E.Author

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October 14, 2019
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Ordered arrays of defect-free GaN nanocolumns with very narrow excitonic emission line width

Publicated to: JOURNAL OF CRYSTAL GROWTH. 525 (UNSP 125189): 125189- - 2019-11-01 525(UNSP 125189), DOI: 10.1016/j.jcrysgro.2019.125189

Authors:

Fernando-Saavedra, A; Albert, S; Bengoechea-Encabo, A; Lopez-Romero, D; Niehle, M; Metzner, S; Schmidt, G; Bertram, F; Sanchez-Garcia, M A; Trampert, A; Christen, J; Calleja, E
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Affiliations

Leibniz Inst Forsch Verbund, Paul Drude Inst Festkorperforsch, Hausvogteipl 5-7, D-10117 Berlin, Germany - Author
Otto von Guericice Univ Magdeburg, Inst Phys, Magdeburg, Germany - Author
Univ Politecn, ISOM Dept Ing Elect, ETSIT, Madrid 28040, Spain - Author
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Abstract

Ordered arrays of very high quality, defect-free GaN nanocolumns were achieved by selective area growth following a two step process involving nanopillar dry etching (top down) and overgrowth by Molecular Beam Epitaxy (bottom up). A study by transmission electron microscopy, over more than 50 individual nanocolumns, confirmed the absence of extended defects, such as dislocations, polarity inversion domain boundaries and stacking faults. Low temperature (10 K) photoluminescence spectrum is dominated by a donor-bound exciton emission line at 3.472 eV with a line width of 0.5 meV. In addition, a distinct emission line from the free-exciton A is observed at 3.479 eV. No traces of emission lines, either at 2.3 eV (Yellow Band); 3.45 eV (also labeled as UX line and recently linked to polarity inversion domain boundaries); or 3.42 eV (stacking faults) were observed.
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Keywords

A1. etchingA1. optical microscopyA3. molecular beam epitaxyB1. nitridesEtchingMolecular beam epitaxyMorphologyNanowiresNitridesOptical microscopySelective-area growth

Quality index

Bibliometric impact. Analysis of the contribution and dissemination channel

The work has been published in the journal JOURNAL OF CRYSTAL GROWTH due to its progression and the good impact it has achieved in recent years, according to the agency Scopus (SJR), it has become a reference in its field. In the year of publication of the work, 2019, it was in position , thus managing to position itself as a Q2 (Segundo Cuartil), in the category Materials Chemistry. Notably, the journal is positioned en el Cuartil Q3 for the agency WoS (JCR) in the category Crystallography.

Independientemente del impacto esperado determinado por el canal de difusión, es importante destacar el impacto real observado de la propia aportación.

Según las diferentes agencias de indexación, el número de citas acumuladas por esta publicación hasta la fecha 2026-04-25:

  • WoS: 7
  • Scopus: 8
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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, from an academic perspective evidenced by the Altmetric agency indicator referring to aggregations made by the personal bibliographic manager Mendeley, gives us a total of: 4.
  • 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: 4 (PlumX).

With a more dissemination-oriented intent and targeting more general audiences, we can observe other more global scores such as:

  • The Total Score from Altmetric: 6.
  • The number of mentions on the social network X (formerly Twitter): 4 (Altmetric).

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/85789/

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: 172
  • Downloads: 2
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Leadership analysis of institutional authors

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

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 (FERNANDO SAAVEDRA, AMALIA LUISA) and Last Author (CALLEJA PARDO, ENRIQUE).

the author responsible for correspondence tasks has been FERNANDO SAAVEDRA, AMALIA LUISA.

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Project objectives

Los objetivos perseguidos en esta aportación se centran en el desarrollo y caracterización de nanocolumnas de GaN de alta calidad. Se propone analizar la viabilidad del crecimiento selectivo mediante un proceso combinado de grabado por nanopilares y sobrecrecimiento por epitaxia de haz molecular. Se busca evaluar la ausencia de defectos extendidos, como dislocaciones, límites de inversión de polaridad y fallos de apilamiento, mediante microscopía electrónica de transmisión en más de 50 nanocolumnas individuales. Además, se pretende determinar las propiedades ópticas a baja temperatura (10 K) mediante espectroscopía de fotoluminiscencia, enfocándose en la emisión excitónica con líneas muy estrechas y la ausencia de emisiones relacionadas con defectos específicos.
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Most relevant results

El estudio presenta resultados destacados sobre el crecimiento de nanocolumnas de GaN libres de defectos mediante un proceso combinado de grabado seco y epitaxia por haz molecular. En primer lugar, la microscopía electrónica de transmisión confirmó la ausencia de defectos extendidos en más de 50 nanocolumnas analizadas, incluyendo dislocaciones, límites de inversión de polaridad y fallos de apilamiento. En segundo lugar, el espectro de fotoluminiscencia a baja temperatura (10 K) mostró una línea de emisión excitónica ligada a donantes en 3.472 eV con un ancho de línea muy estrecho de 0.5 meV. Además, se detectó una línea de emisión clara del excitón libre A a 3.479 eV. Finalmente, no se observaron emisiones asociadas a bandas amarillas (2.3 eV), líneas UX (3.45 eV) ni fallos de apilamiento (3.42 eV).
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Awards linked to the item

The Spanish team wish to acknowledge partial financial support by the Spanish project MICINN MAT2015-65120-R. Furthermore, we thank the German Research Foundation (DFG) for financial support within the Research Instrumentation Program INST 272/148-1 and the Collaborative Research Center SFB 787 Semiconductor Nanophotonics: Materials, Models, Devices M. Niehle and A. Trampert acknowledge financial support from the State of Berlin and the European Regional Development Fund under contract number grant agreement No. 2016011843.
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