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Title
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Compositional analysis based on electron holography and a chemically sensitive reflection
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Author
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Abstract
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| A method for compositional analysis of low-dimensional heterostructures is presented. The suggested procedure is based on electron holography and the exploitation of the chemically sensitive (0 0 2) reflection. We apply an off-axis imaging condition with the (0 0 2) beam strongly excited and centered on the optic axis. The first side band of the hologram is centered using an "empty" reference hologram obtained for a hole of the specimen. From the centered side band we use the phase of the central (0 0 0) and the amplitude of the (0 0 2) reflections to evaluate the local composition and the local specimen thickness in an iterative and self-consistent way. Delocalization effects that lead to a shift of the spatial information of (0 0 0) and (0 0 2) reflections are taken into account. The application of the procedure is demonstrated with an AlAs/GaAs(0 0 1) superlattice with a period of 5 nm. The concentration profiles obtained are discussed in relation to segregation. The measured segregation efficiency is R = 0.51 +/- 0.02. (C) 2001 Elsevier Science B.V. All rights reserved. |
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Language
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English
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Source (journal)
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Ultramicroscopy. - Amsterdam
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Publication
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Amsterdam
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2001
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ISSN
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0304-3991
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Volume/pages
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88
:1
(2001)
, p. 51-61
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ISI
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000168940900005
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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