Coherent diffraction imaging of a single epitaxial InAs nanowire using a focused x-ray beam

Abstract

International audienc

Displacement field of a screw dislocation in a〈011〉Cu nanowire: An atomistic study

“…In terms of stress, this problem consists in solving the two relevant σ img rz and σ img θz stress components that are solutions of both the equilibrium [Eq. (6) (15)]. In the present work, the full solution u tot z of this problem is resolved by performing atomistic simulations.…”

“…At that time, only the diffraction pattern caused by the isotropic displacement u ∞,i z = bθ/2π was known from Wilson calculations. 29,30 Nowadays, it becomes possible to perform coherent x-ray diffraction on a single nanowire 6,7 and from the atomistic simulations to get a lot of information on the predicted diffractogram. 15 The aim of this section is to investigate the effect on the 044 reflection of each contribution (i.e., anisotropy, dislocation core, surface effects, image effects, twist) to the total u z field caused by an axial screw dislocation in a [011] circular copper nanowire.…”

“…5 Other studies based on sophisticated x-ray diffraction techniques are currently carried out to resolve the displacement field in these nanosystems. [6][7][8] One significant advance would be, for instance, to identify a single screw dislocation in a single nanowire in order to correlate the influence of this defect to the mechanical properties of the nanowire.…”

Three-Dimensional X-Ray Fourier Transform Holography: The Bragg Case

“…The monochromatic beam (wavelength ¼ 0:154 nm) was delivered by a Si-111 monochromator (energy bandwidth of about 1:4 Â 10 À4 ), resulting in a longitudinal coherence length of about 1 m. To increase the flux on the sample, a coherently illuminated Fresnel zone plate made of Au was placed 129 mm upstream [17]. Further details on the focusing setup are given in [18]. The measured size of the focused beam (full width at half maximum) was about 350 and 400 nm in the vertical and horizontal directions, respectively.…”

X-ray diffraction strain analysis of a single axial InAs1–xPxnanowire segment

“…However, in this way the position of the X-ray spot on the sample can only be determined within a precision of a few micrometres. A finer alignment followed using scanning diffraction microscopy, as described by Diaz et al (2009): by setting the detector and sample angle being sensitive to the NW signal, one records the intensity while moving the sample laterally. This gives a realspace map of the NW positions with a resolution according to the focused X-ray beam size.…”