20 / 22
Crystallography 2018
Structural Chemistry & Crystallography Communication
ISSN: 2470-9905
Page 72
June 04-05, 2018
London, UK
3
rd
Edition of International Conference on
Advanced Spectroscopy,
Crystallography and Applications
in Modern Chemistry
X
-ray diffraction has long been used to investigate the
properties of materials such as crystalline thin films.
X-rays have the advantage over more surface-sensitive
imaging modalities, such as atomic force microscopy, electron
microscopy or photoemission electron microscopy because they
can penetrate the entire sample. Bragg projection ptychography
(BPP) is a coherent x-ray diffraction imaging technique which
combines the advantages of scanningmicroscopy with the phase
contrast of X-ray ptychography. Our research applies it for high
resolution imaging of the phase-shifted crystalline domains
associated with epitaxial growth. The distinct advantages of BPP
are that the spatial extent of the sample is arbitrarily-defined, it
is also non-destructive and it gives potentially diffraction limited
spatial resolution at high brilliance 3rd generation synchrotron
radiation facilities. Here we demonstrate the application of BPP
for revealing the domain structure caused by epitaxial misfit
in a nanostructured metallic thin film. Experimental coherent
diffraction datawere collected froma niobium thin film, epitaxially
grown on a sapphire substrate as the beam was scanned across
the sample. The data were analysed by BPP using a carefully
selected combination of refinement procedures. The resulting
image shows a close packed array of epitaxial domains, shifted
with respect to each other due to misfit between the film and its
substrate. Bragg coherent imaging methods have the “dark field”
advantage that they only consider signals from the parts of the
sample that are contributing to the Bragg peak; all other sources
of scattering and contributions from other components of the
sample are suppressed.
Xiaowen.shi@diamond.ac.ukBRAGG PROJECTION PTYCHOGRAPHY ON LOW-DIMENSIONAL MATERIALS
Xiaowen Shi
Diamond Light Source, United Kingdom
Struct Chem Crystallogr Commun 2018, Volume 4
DOI: 10.21767/2470-9905-C1-006