Formation and Characterization of 1.5-Monolayer Self-Assembled InAs/GaAs Quantum Dots Using Postgrowth Annealing

In this paper, we report that low-density InAs/GaAs quantum dots (QDs) can be formed by postgrowth annealing the samples with 1.5-monolayer (ML) InAs coverage, which is thinner than the critical layer thickness for the Stranski-Krastanov growth. The annealing procedure was performed immediately afte...

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Bibliographic Details
Published in:IEEE transactions on nanotechnology 2007-11, Vol.6 (6), p.589-594
Main Authors: HUANG, Chun-Yuan, OU, Tzu-Min, CHOU, Shu-Ting, WU, Meng-Chyi, LIN, Shih-Yen, CHI, Jim-Yong
Format: Article
Language:English
Subjects:
Annealing
Cross-disciplinary physics: materials science
rheology
Density
Epitaxial growth
Exact sciences and technology
Gallium arsenide
Gallium arsenides
Indium arsenides
Materials science
Molecular beam epitaxial growth
Nanoscale materials and structures: fabrication and characterization
Photodetectors
Physics
Quantum dot lasers
Quantum dots
Rapid thermal annealing
self-assembled quantum dots
Semiconductor lasers
semiconductor materials
Solvents
Substrates
Surface emitting lasers
Temperature
Wetting
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Summary:In this paper, we report that low-density InAs/GaAs quantum dots (QDs) can be formed by postgrowth annealing the samples with 1.5-monolayer (ML) InAs coverage, which is thinner than the critical layer thickness for the Stranski-Krastanov growth. The annealing procedure was performed immediately after the deposition of the InAs layer. The effects of annealing time and annealing temperature on the dot density, dot size, and optical characteristics of the QDs were investigated. The optimum annealing conditions to obtain low-density QDs are longer than 60 s and higher than 500degC . Meanwhile, no luminescence can be observed for the wetting-layer, which may suggest that the postgrowth annealing will make the wetting layer thinner and thus reduce the effects of wetting layer on carrier relaxation and recombination. On the other hand, we observe that a decrease of the PL intensity at the annealing conditions of 60 s and 515degC , which is possibly due to the increasing surface dislocations resulted from the In adatom desorption at higher annealing temperature.
ISSN:1536-125X
1941-0085
DOI:10.1109/TNANO.2007.907847