High efficient luminescence in type-II GaAsSb-capped InAs quantum dots upon annealing

The photoluminescence efficiency of GaAsSb-capped InAs/GaAs type II quantum dots (QDs) can be greatly enhanced by rapid thermal annealing while preserving long radiative lifetimes which are ∼20 times larger than in standard GaAs-capped InAs/GaAs QDs. Despite the reduced electron-hole wavefunction ov...

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Bibliographic Details
Published in:Applied physics letters 2012-12, Vol.101 (25)
Main Authors: Ulloa, J. M., Llorens, J. M., Alén, B., Reyes, D. F., Sales, D. L., González, D., Hierro, A.
Format: Article
Language:English
Subjects:
Annealing
Capping
Gallium arsenide
Gallium arsenides
Indium arsenides
Luminescence
Quantum dots
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Summary:The photoluminescence efficiency of GaAsSb-capped InAs/GaAs type II quantum dots (QDs) can be greatly enhanced by rapid thermal annealing while preserving long radiative lifetimes which are ∼20 times larger than in standard GaAs-capped InAs/GaAs QDs. Despite the reduced electron-hole wavefunction overlap, the type-II samples are more efficient than the type-I counterparts in terms of luminescence, showing a great potential for device applications. Strain-driven In-Ga intermixing during annealing is found to modify the QD shape and composition, while As-Sb exchange is inhibited, allowing to keep the type-II structure. Sb is only redistributed within the capping layer giving rise to a more homogeneous composition.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4773008