High-resolution X-ray diffractometry includes a series of advanced non-destructive X-ray scattering technqiues, mainly a) specular reflectivity, b) double-axis diffraction, and c) triple-axis diffraction and reciprocal space mapping. In these techniques, the incident X-ray beam is monochromated and collimated by up to eight multi-crystal reflections, and X-rays diffracted from the sample may be further analyzed by two or four reflections. This pseudo-plane-wave scattering process makes the strain sensitivity of the diffractometer better than 10-6, which is well suited to determination of lattice constants, strains, compositions, and dopant concentrations. X-ray specular reflectivity is a powerful method for measuring the electron density, thickness, and surface/interface roughness of single-crystal, polycrystalline, or amorphous thin films and multilayers with the film thickness from nanometers to submicrons. Double- and triple-axis diffraction techniques are mainly suitable and powerful for characterization of nanostructures in single crystal and epitaxial systems, such as quantum wells/wires/dots. For one-dimensional multilayers and superlattice, high-resolution diffraction can accurately reveal the detailed structural properties of each individual layer due to its incomparable high strain sensitivity. For two- or three-dimensional structures, these diffraction methods yield signals over many quantum objects to give mean structural parameters. However, this makes it possible to study the ordering, correlation, size and orientation homogeneity, and the strain states of the objects either located on the surface or buried inside the crystal. The other advantage of high-resolution diffraction is that most of the measured structural information can be quantified on the basis of ideal structure models although this involves complicated X-ray dynamical diffraction theory. In this presentation, we well illustrate the basic principles, interpretation theories, and experimental schemes of high-resolution diffraction techniques for nanostructure characterization. Some application examples will also be presented.

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7/11/2002