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Threefold rotational symmetry in hexagonally shaped core–shell (In,Ga)As/GaAs nanowires revealed by coherent X‐ray diffraction imaging
Author(s) -
Davtyan Arman,
Krause Thilo,
Kriegner Dominik,
Al-Hassan Ali,
Bahrami Danial,
Mostafavi Kashani Seyed Mohammad,
Lewis Ryan B.,
Küpers Hanno,
Tahraoui Abbes,
Geelhaar Lutz,
Hanke Michael,
Leake Steven John,
Loffeld Otmar,
Pietsch Ullrich
Publication year - 2017
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576717004149
Subject(s) - nanowire , diffraction , shell (structure) , scattering , materials science , bragg's law , condensed matter physics , phase (matter) , x ray crystallography , molecular physics , core (optical fiber) , crystallography , optics , physics , chemistry , nanotechnology , quantum mechanics , composite material
Coherent X‐ray diffraction imaging at symmetric hhh Bragg reflections was used to resolve the structure of GaAs/In 0.15 Ga 0.85 As/GaAs core–shell–shell nanowires grown on a silicon (111) substrate. Diffraction amplitudes in the vicinity of GaAs 111 and GaAs 333 reflections were used to reconstruct the lost phase information. It is demonstrated that the structure of the core–shell–shell nanowire can be identified by means of phase contrast. Interestingly, it is found that both scattered intensity in the (111) plane and the reconstructed scattering phase show an additional threefold symmetry superimposed with the shape function of the investigated hexagonal nanowires. In order to find the origin of this threefold symmetry, elasticity calculations were performed using the finite element method and subsequent kinematic diffraction simulations. These suggest that a non‐hexagonal (In,Ga)As shell covering the hexagonal GaAs core might be responsible for the observation.