Effect of annealing in the Sb and In distribution of type II GaAsSb-capped InAs quantum dots

Reyes, D.F. and Ulloa Herrero, José María and Fernández González, Alvaro de Guzmán and Hierro Cano, Adrián and Sales, D.L. and Beanland, R. and Sánchez, A.M. and González, D. (2015). Effect of annealing in the Sb and In distribution of type II GaAsSb-capped InAs quantum dots. "Semiconductor Science and Technology", v. 30 (n. 11); pp. 1-9. ISSN 0268-1242. https://doi.org/10.1088/0268-1242/30/11/114006.

Description

Title: Effect of annealing in the Sb and In distribution of type II GaAsSb-capped InAs quantum dots
Author/s:
  • Reyes, D.F.
  • Ulloa Herrero, José María
  • Fernández González, Alvaro de Guzmán
  • Hierro Cano, Adrián
  • Sales, D.L.
  • Beanland, R.
  • Sánchez, A.M.
  • González, D.
Item Type: Article
Título de Revista/Publicación: Semiconductor Science and Technology
Date: 2015
ISSN: 0268-1242
Volume: 30
Subjects:
Freetext Keywords: III-V quantum dots, GaAsSb, Sb distribution, Strain state, annealed, TEM
Faculty: Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM) (UPM)
Department: Otro
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Type II emission optoelectronic devices using GaAsSb strain reduction layers (SRL) over InAs quantum dots (QDs) have aroused great interest. Recent studies have demonstrated an extraordinary increase in photoluminescence (PL) intensity maintaining type II emission after a rapid thermal anneal (RTA), but with an undesirable blueshift. In this work, we have characterized the effect of RTA on InAs/GaAs QDs embedded in a SRL of GaAsSb by transmission electron microscopy (TEM) and finite element simulations. We find that annealing alters both the distribution of Sb in the SRL as well as the exchange of cations (In and Ga) between the QDs and the SRL. First, annealing causes modifications in the capping layer, reducing its thickness but maintaining the maximum Sb content and improving its homogeneity. In addition, the formation of Sb-rich clusters with loop dislocations is noticed, which seems not to be an impediment for an increased PL intensity. Second, RTA produces flatter QDs with larger base diameter and induces a more homogeneous QD height distribution. The Sb is accumulated over the QDs and the RTA enlarges the Sb-rich region, but the Sb contents are very similar. This fact leaves the type II alignment without major changes. Atomic-scale strain analysis of the nanostructures reveal a strong intermixing of In/Ga between the QDs and the capping layer, which is the main responsible mechanism of the PL blueshift. The improvement of the crystalline quality of the capping layer together with higher homogeneity QD sizes could be the origin of the enhancement of the PL emission.

Funding Projects

TypeCodeAcronymLeaderTitle
Government of SpainMAT2010-15206UnspecifiedUnspecifiedUnspecified
Government of SpainMAT2013- 47102-C2UnspecifiedUnspecifiedUnspecified

More information

Item ID: 41477
DC Identifier: http://oa.upm.es/41477/
OAI Identifier: oai:oa.upm.es:41477
DOI: 10.1088/0268-1242/30/11/114006
Official URL: http://iopscience.iop.org/article/10.1088/0268-1242/30/11/114006/meta
Deposited by: Memoria Investigacion
Deposited on: 07 Sep 2016 17:04
Last Modified: 07 Jun 2019 16:24
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