Tuning vertically stacked InAs/GaAs quantum dot properties under spacer thickness effects for 1.3 {/content/J5P4L37MCDDJRV1K/xhuge956.gif}m emission

Coherent InAs islands separated by GaAs spacer (d) layers are shown to exhibit self-organized growth along the vertical direction. A vertically stacked layer structure is useful for controlling the size distribution of quantum dots. The thickness of the GaAs spacer has been varied to study its influ...

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Bibliographic Details
Published in:Applied physics. A, Materials science & processing Materials science & processing, 2004-08, Vol.79 (3), p.587-591
Main Authors: Bouzaiene, L, Ilahi, B, Sfaxi, L, Hassen, F, Maaref, H, Marty, O, Dazord, J
Format: Article
Language:English
Subjects:
Gallium arsenide
Gallium arsenides
Indium arsenides
Interruption
Optical properties
Quantum dots
Spacers
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Summary:Coherent InAs islands separated by GaAs spacer (d) layers are shown to exhibit self-organized growth along the vertical direction. A vertically stacked layer structure is useful for controlling the size distribution of quantum dots. The thickness of the GaAs spacer has been varied to study its influence on the structural and optical properties. The structural and optical properties of multilayer InAs/GaAs quantum dots (QDs) have been investigated by atomic force microscopy (AFM), transmission electron microscopy (TEM), and photoluminescence (PL) measurements. The PL full width at half maximum (FWHM), reflecting the size distribution of the QDs, was found to reach a minimum for an inter-dots GaAs spacer layer thickness of 30 monolayers (ML). For the optimized structure, the TEM image shows that multilayer QDs align vertically in stacks with no observation of apparent structural defects. Furthermore, AFM images showed an improvement of the size uniformity of the QDs in the last layer of QDs with respect to the first one. The effect of growth interruption on the optical properties of the optimized sample (E30) was investigated by PL. The observed red shift is attributed to the evolution of the InAs islands during the growth interruption. We show the possibility of increasing the size of the QDs approaching the strategically important 1.3 {/content/J5P4L37MCDDJRV1K/xxlarge956.gif}m wavelength range (at room temperature) with growth interruption after InAs QD deposition.
ISSN:0947-8396
1432-0630
DOI:10.1007/s00339-003-2455-3