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Specular reflection intensity modulated by grazing‐incidence diffraction in a wide angular range
Author(s) -
Nikolaev K. V.,
Makhotkin I. A.,
Yakunin S. N.,
Kruijs R. W. E. van de,
Chuev M. A.,
Bijkerk F.
Publication year - 2018
Publication title -
acta crystallographica section a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.742
H-Index - 83
ISSN - 2053-2733
DOI - 10.1107/s2053273318008963
Subject(s) - specular reflection , diffraction , diffractometer , optics , materials science , crystal (programming language) , reflection (computer programming) , azimuth , single crystal , characterization (materials science) , crystallography , physics , chemistry , computer science , programming language , scanning electron microscope
Grazing‐incidence X‐ray diffraction (GID) is a well known technique for the characterization of crystal surfaces. A theoretical study has been performed of the sensitivity of GID to the structure of a crystal surface and distorted nanometre‐thin surface layers. To simulate GID from crystals that have a complex subsurface structure, a matrix formalism of the dynamical diffraction theory has been applied. It has been found that the azimuthal rocking curves of a crystal that has a distorted subsurface, measured over a wide angular range, show asymmetric thickness oscillations with two distinguishable sets of frequencies: one corresponding to the diffraction in the single‐crystal subsurface layer and the second corresponding to the diffraction in the single‐crystal substrate. Therefore, azimuthal rocking curves allow characterization of the subsurface structure of a single crystal. Furthermore, thickness oscillations induced by evanescent diffraction modulate the specular reflection intensity, showing high‐intensity modulations. This will potentially allow implementation of subsurface crystal characterization using, for instance, a laboratory‐scale X‐ray diffractometer.