High-resolution three-dimensional reciprocal-space mapping of InAs nanowires

Grazing-incidence X-ray diffraction is combined with a two-dimensional pixel detector to obtain three-dimensional reciprocal-space maps of InAs nanowires grown by molecular beam epitaxy. This rapid data-acquisition technique and the necessary correction factors are described in general terms, as well as for the specific setup used, for which a resolution of ∼2 × 10⁻³ Å is computed. The three-dimensional data sets are obtained by calculating the reciprocal space coordinates for every pixel in the detected images, and are used to map the diffuse scattering from the nanowires as both two-dimensional reciprocal-space maps and three-dimensional isosurfaces. The InAs nanowires are shown to consist mainly of wurtzite crystal with a c/a ratio of 1.641. The diffuse scattering reveals two different facet structures, both resulting in hexagonal cross sections of the nanowires.