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Small‐angle X‐ray scattering from GaN nanowires on Si(111): facet truncation rods, facet roughness and Porod's law
Author(s) -
Kaganer Vladimir M.,
Konovalov Oleg V.,
Fernández-Garrido Sergio
Publication year - 2021
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/s205327332001548x
Subject(s) - scattering , facet (psychology) , rod , surface finish , optics , condensed matter physics , surface roughness , intensity (physics) , nanowire , materials science , small angle x ray scattering , physics , molecular physics , optoelectronics , medicine , psychology , social psychology , alternative medicine , personality , pathology , composite material , big five personality traits
Small‐angle X‐ray scattering from GaN nanowires grown on Si(111) is measured in the grazing‐incidence geometry and modelled by means of a Monte Carlo simulation that takes into account the orientational distribution of the faceted nanowires and the roughness of their side facets. It is found that the scattering intensity at large wavevectors does not follow Porod's law I ( q ) ∝ q −4 . The intensity depends on the orientation of the side facets with respect to the incident X‐ray beam. It is maximum when the scattering vector is directed along a facet normal, reminiscent of surface truncation rod scattering. At large wavevectors q , the scattering intensity is reduced by surface roughness. A root‐mean‐square roughness of 0.9 nm, which is the height of just 3–4 atomic steps per micrometre‐long facet, already gives rise to a strong intensity reduction.