Interferometric Diffraction from Amorphous Double Films

Aram Rezikyan, James A. Belcourt, Michael Treacy

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

We explore the interference fringes that arise in diffraction patterns from double-layer amorphous samples where there is a substantial separation, up to about a micron, between two overlapping thin films. This interferometric diffraction geometry, where both waves have interacted with the specimen, reveals phase gradients within microdiffraction patterns. The rapid fading of the observed fringes as the magnitude of the diffraction vector increases confirms that displacement decoherence is strong in high-energy electron scattering from amorphous samples. The fading of fringes with increasing layer separation indicates an effective illumination coherence length of about 225 nm, which is consistent with the value of 270 nm expected for the heated Schottky field emitter source. A small reduction in measured coherence length is expected because of the additional energy spread induced in the beam after it passes through the first layer.

Original languageEnglish (US)
Pages (from-to)1348-1360
Number of pages13
JournalMicroscopy and Microanalysis
Volume21
Issue number5
DOIs
StatePublished - Mar 5 2015

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Keywords

  • amorphous double layer
  • interference fringes
  • interferometric diffraction

ASJC Scopus subject areas

  • Instrumentation

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