Three-dimensional imaging of crystal defects by `topo-tomography'

Abstract

A new technique,`topo-tomography', suitable for the characterization of the three-dimensional defect structure in bulk crystals, is proposed. The technique consists of the combination of diffraction topography and microtomography. It is applicable to high-quality single crystals, provided that the`direct image' is the dominant contrast mechanism. In this case, crystal defects give rise to locally enhanced intensity compared with the perfect-crystal matrix. The additional intensities sum along the diffracted-beam direction and yield projections of the local Bragg re¯ectivity. Like in the case of absorption tomography, the threedimensional distribution of this re¯ectivity can be reconstructed from a large number of projections. The ®rst experimental results of this technique, applied to a synthetic diamond crystal, are presented.

X-ray micro-beam characterization of lattice rotations and distortions due to an individual dislocation

“…X-rays provide an alternative means of characterizing dislocations in the bulk without the need for sectioning. X-ray topography, which relies on the extinction contrast formed when the crystal lattice moves out of the Bragg condition, allows bulk single dislocation imaging 12 . However, it is confined to samples with small lattice rotations and low dislocation densities, and does not provide direct quantitative information, greatly limiting its range of applications.…”

Combining 3DXRD and Absorption Contrast Tomography

“…Ludwig has suggested that one could combine diffraction with microtomography by applying the same geometry as in topo-tomography 2 [18]. The pro-2 Topo-tomography is a novel technique due to Ludwig and coworkers [18].…”

“…The pro-2 Topo-tomography is a novel technique due to Ludwig and coworkers [18]. It is an extension of conventional x-ray topography, which allows visualization of longrange strain fields, induced, for example, by crystalline defects such as inclusions or individual dislocations [19,20].…”

Characterization of VGFB-grown ZnTe single crystals by means of synchrotron X-ray topo-tomographic technique

“…In the early stages of the development of X-ray topographic techniques, stereotopographs were often recorded as a pair in the hkl and -h-k-l reflections [3], or recorded as a pair rotated by 781 about the diffraction vector [4]. Recently, a new technique, topo-tomography, has been developed at the ID-19 beamline of the European Synchrotron Radiation Facility (ESRF, Grenoble, France), which combines tomography and topographic imaging [5]. The technique has allowed us to analyze the configuration of individual dislocations inside a low-absorbing high-quality single crystal, e.g.…”