EPSRC Reference: |
GR/H92838/01 |
Title: |
STUDY OF MATERIALS BY COHERENT ELECTRON DIFFRACTION AND BY ELECTRON HOLOGRAPHY |
Principal Investigator: |
Vincent, Dr R |
Other Investigators: |
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Researcher Co-Investigators: |
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Project Partners: |
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Department: |
Physics |
Organisation: |
University of Bristol |
Scheme: |
Standard Research (Pre-FEC) |
Starts: |
01 April 1993 |
Ends: |
31 December 1996 |
Value (£): |
133,313
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EPSRC Research Topic Classifications: |
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EPSRC Industrial Sector Classifications: |
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Related Grants: |
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Panel History: |
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Summary on Grant Application Form |
Recent experiments have shown that the Hitachi HF-2000 electron microscope equipped with a cold field emission source provides a coherent beam with a minimum probe size of 0.6nm. The overlaps between adjacent discs in convergent beam patterns show interference fringes that directly phase the reflections, both in low order reflections and in higher order Laue zone reflections excited around a zone axis. The angular field included within the overlap region is expanded by a large angle technique, where an aperture limits the number of beams that contribute to the interference pattern. We plan to study coherent diffraction contrast in crystals where the focused probe size is smaller than the unit cell, with the aim of structure determination for new metastable phases. As an alternative to electron holography in diffraction space, off-axis holograms in real space will be produced by interfering beams with a biprism, where the proposed reference fringe spacing of 1+ is equivalent to a spatial resolution of 3+. Applications include mapping of piezo-electric and magnetic fields in semiconductors and measurement of shifts in the inner potential across interfaces in semiconductor multilayers and at boundaries with amorphous layers.
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Key Findings |
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Potential use in non-academic contexts |
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Impacts |
Description |
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Summary |
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Date Materialised |
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Sectors submitted by the Researcher |
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Project URL: |
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Further Information: |
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Organisation Website: |
http://www.bris.ac.uk |