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Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/12170

Title: Stranski-Krastanow growth of multilayer In(Ga)As/GaAs QDs on Germanium substrate
Authors: BANERJEE, S
HALDER, N
CHAKRABARTI, S
Keywords: molecular-beam epitaxy
inas/gaas quantum dots
migration-enhanced epitaxy
optical-properties
ge substrate
gaas
quality
layer
Issue Date: 2010
Publisher: SPRINGER
Citation: APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 99(4), 791-795
Abstract: We have described Stranski-Krastanow growth of multilayer In(Ga)As/GaAs QDs on Ge substrate by MBE. The growth technique includes deposition of a thin germanium buffer layer followed by migration-enhanced epitaxy (MEE) grown GaAs layer at 350A degrees C. The MEE layer was overgrown by a thin low-temperature (475A degrees C) grown GaAs layer with a subsequent deposition of a thick GaAs layer grown at 590A degrees C. The sample was characterized by AFM, cross-sectional TEM and temperature-dependent PL measurements. The AFM shows dense formation of QDs with no undulation in the wetting layer. The XTEM image confirms that the sample is free from structural defects. The 8 K PL emission exhibits a 1051 nm peak, which is similar to the control sample consisting of In(Ga)As/GaAs QDs grown on GaAs substrate, but the observed emission intensity is lower. The similar slopes of Arrhenius plot of the integrated PL intensity for the as-grown QD sample grown on Ge substrate as well as for a reference QD sample grown on GaAs substrate are found to be identical, indicating a similar carrier emission process for both the samples. This in turn indicates coherent formation of QDs on Ge substrate. We presume due to the accumulated strain associated with the self-assembled growth of nanostructures on Ge that nonradiative recombination centers are introduced in the GaAs barrier in between the QD layers, which in turn degrades the overall optical quality of the sample.
URI: http://dx.doi.org/10.1007/s00339-010-5727-8
http://dspace.library.iitb.ac.in/xmlui/handle/10054/12170
http://hdl.handle.net/10054/12170
ISSN: 0947-8396
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