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Title: GaAsSb-capped InAs quantum dots: From enlarged quantum dot height to alloy fluctuations

Abstract

The Sb-induced changes in the optical properties of GaAsSb-capped InAs/GaAs quantum dots (QDs) are shown to be strongly correlated with structural changes. The observed redshift of the photoluminescence emission is shown to follow two different regimes. In the first regime, with Sb concentrations up to approx12%, the emission wavelength shifts up to approx1280 nm with a large enhancement of the luminescence characteristics. A structural analysis at the atomic scale by cross-sectional scanning tunneling microscopy shows that this enhancement arises from a gradual increase in QD height, which improves carrier confinement and reduces the sensitivity of the excitonic band gap to QD size fluctuations within the ensemble. The increased QD height results from the progressive suppression of QD decomposition during the capping process due to the presence of Sb atoms on the growth surface. In the second regime, with Sb concentrations above approx12%, the emission wavelength shifts up to approx1500 nm, but the luminescence characteristics progressively degrade with the Sb content. This degradation at high Sb contents occurs as a result of composition modulation in the capping layer and strain-induced Sb migration to the top of the QDs, together with a transition to a type-II band alignment.

Authors:
; ; ; ;  [1]; ;  [2]
  1. Institute for Systems based on Optoelectronics and Microtechnology (ISOM), Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)
  2. Photonics and Semiconductor Nanophysics, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven (Netherlands)
Publication Date:
OSTI Identifier:
21366733
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 81; Journal Issue: 16; Other Information: DOI: 10.1103/PhysRevB.81.165305; (c) 2010 The American Physical Society; Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANTIMONY ALLOYS; ARSENIC ALLOYS; DECOMPOSITION; FLUCTUATIONS; GALLIUM ALLOYS; GALLIUM ARSENIDES; INDIUM ARSENIDES; LAYERS; MIGRATION; MODULATION; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; QUANTUM DOTS; RED SHIFT; SCANNING TUNNELING MICROSCOPY; SENSITIVITY; STRAINS; SURFACES; TERNARY ALLOY SYSTEMS; WAVELENGTHS; ALLOY SYSTEMS; ALLOYS; ARSENIC COMPOUNDS; ARSENIDES; CHEMICAL REACTIONS; EMISSION; GALLIUM COMPOUNDS; INDIUM COMPOUNDS; LUMINESCENCE; MICROSCOPY; NANOSTRUCTURES; PHOTON EMISSION; PHYSICAL PROPERTIES; PNICTIDES; VARIATIONS

Citation Formats

Ulloa, J M, Gargallo-Caballero, R, Moral, M del, Guzman, A, Hierro, A, Bozkurt, M, and Koenraad, P M. GaAsSb-capped InAs quantum dots: From enlarged quantum dot height to alloy fluctuations. United States: N. p., 2010. Web. doi:10.1103/PHYSREVB.81.165305.
Ulloa, J M, Gargallo-Caballero, R, Moral, M del, Guzman, A, Hierro, A, Bozkurt, M, & Koenraad, P M. GaAsSb-capped InAs quantum dots: From enlarged quantum dot height to alloy fluctuations. United States. https://doi.org/10.1103/PHYSREVB.81.165305
Ulloa, J M, Gargallo-Caballero, R, Moral, M del, Guzman, A, Hierro, A, Bozkurt, M, and Koenraad, P M. 2010. "GaAsSb-capped InAs quantum dots: From enlarged quantum dot height to alloy fluctuations". United States. https://doi.org/10.1103/PHYSREVB.81.165305.
@article{osti_21366733,
title = {GaAsSb-capped InAs quantum dots: From enlarged quantum dot height to alloy fluctuations},
author = {Ulloa, J M and Gargallo-Caballero, R and Moral, M del and Guzman, A and Hierro, A and Bozkurt, M and Koenraad, P M},
abstractNote = {The Sb-induced changes in the optical properties of GaAsSb-capped InAs/GaAs quantum dots (QDs) are shown to be strongly correlated with structural changes. The observed redshift of the photoluminescence emission is shown to follow two different regimes. In the first regime, with Sb concentrations up to approx12%, the emission wavelength shifts up to approx1280 nm with a large enhancement of the luminescence characteristics. A structural analysis at the atomic scale by cross-sectional scanning tunneling microscopy shows that this enhancement arises from a gradual increase in QD height, which improves carrier confinement and reduces the sensitivity of the excitonic band gap to QD size fluctuations within the ensemble. The increased QD height results from the progressive suppression of QD decomposition during the capping process due to the presence of Sb atoms on the growth surface. In the second regime, with Sb concentrations above approx12%, the emission wavelength shifts up to approx1500 nm, but the luminescence characteristics progressively degrade with the Sb content. This degradation at high Sb contents occurs as a result of composition modulation in the capping layer and strain-induced Sb migration to the top of the QDs, together with a transition to a type-II band alignment.},
doi = {10.1103/PHYSREVB.81.165305},
url = {https://www.osti.gov/biblio/21366733}, journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 16,
volume = 81,
place = {United States},
year = {Thu Apr 15 00:00:00 EDT 2010},
month = {Thu Apr 15 00:00:00 EDT 2010}
}