SXRD

Scanning X-ray diffraction (SXRD) is a diffraction method used to characterize crystalline materials by recording the distribution of scattered X-rays as the sample or beam is scanned. In SXRD, a focused X-ray beam is raster-scanned across the sample and the intensity of scattered X-rays is measured, often with a two-dimensional area detector or a point detector with a goniometer. The resulting data form reciprocal-space maps that reveal local variations in lattice spacing and orientation.

SXRD can be implemented with laboratory X-ray sources or at synchrotron facilities, with grazing-incidence SXRD (GI-SXRD) being a common variant. GI-SXRD uses shallow X-ray incidence to enhance sensitivity to surfaces and thin films, enabling detailed studies of interfaces and layered structures.

What is measured in SXRD includes peak positions, which yield lattice parameters; peak widths, which inform about crystalline quality, domain size, and microstrain; and diffuse scattering, which provides insight into defects and inhomogeneities. By performing scans over multiple angles or using reciprocal-space mapping, researchers can extract information about film thickness, interface roughness, strain distribution, and mosaic spread within a sample.

Applications of SXRD span materials science, semiconductor device research, oxide and perovskite thin films, and two-dimensional materials. It is particularly valuable for elucidating structural properties of epitaxial films, multilayers, and surfaces where local structural information is essential.

Advantages of SXRD include non-destructive analysis and the ability to map structural variations at micron to sub-micron scales. Limitations involve the need for bright X-ray sources (often synchrotrons), careful alignment and calibration, longer data collection times, and potential radiation damage or data analysis complexity.