Atomic scale interface engineering for strain compensated epitaxially grown InAs/AlSb superlattices.
This paper presents a systematic investigation of strain compensation schemes for InAs/AlSb superlattices (SLs) on GaSb substrates. Short growth interruptions (soak times) under varying arsenic and/or antimony beam equivalent pressures in InAs/AlSb SLs with exemplary dimensions of about ((2.4/2.4) ± 0.2) nm were investigated to achieve strain compensation. When using uncracked As(4), strain compensation was found to be unaccomplishable unless sub-monolayer AlAs spikes were inserted at the InAs → AlSb interface. In contrast, the supply of cracked As(2) dimers leads directly to the formation of strain compensating AlAs-like interfaces. This mechanism allows various growth sequences for strain compensated superlattices, including soak-time-free and Sb-soak-only SL growth. Each of the two latter approaches yields layers with excellent crystal quality and minimal intermixing at the heterointerfaces as verified by high resolution x-ray diffraction analysis and transmission electron microscopy.
Technische Physik, Physikalisches Institut, Julius-Maximilians-Universität Würzburg, Würzburg, Germany. adam.bauer@physik.uni-wuerzburg.de
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Bauer
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Dallner
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Herrmann
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Lehnhardt
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Kamp
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Höfling
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Worschech
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Forchel