Progress in fabrication of the optoelectronic devices based on epitaxial thin-films and semiconductor multilayer structures, requires an improvements of techniques used for the material characterization.

The method in a skew asymmetric arrangement of X-ray diffraction in Bragg geometry for a structural diagnostic of defected and multi-layers semiconductor materials is presented. New possibilities of this method for a layer-by-layer visualization of structural changes in subsurface crystal layers are demonstrated for semiconductor materials after various types of surface treatments such as a chemical etching, laser irradiation and ion implantation.

The lattice strain and structural changes in materials produced by existing and introduced defects ware characterized by a combination of X-ray topography and diffraction techniques using single- and double-crystal configurations in the symmetric, asymmetric and skew-asymmetric geometries. Finally, to visualise of microstructural changes and to compare with their theoretical models, X-ray structural investigation was accompanied by transmission electron microscopy, scanning electron microscopy, atomic force microscopy and secondary ion mass spectroscopy measurements.

To build a full possible picture of microstructure of such materials, the simulation and interpretation of diffraction reflection curves of crystalline structures with a heterogeneous near-surface layer have been performed on the basis of a kinematics diffraction theory, analytical solutions of the Takagi-Topan equations in semi-kinematics approximation and generalized dynamic theory of X-ray scattering. Moreover, additional simulations of processes of defects generation in model materials caused by an ion implantation and dopant diffusion were carried out.

The presented method in this skew-asymmetrical mode is both a recommendable and useful tool for studying epitaxial thin films as well as multi-layer systems.

1. Characterization and properties of a modified NiTi shape memory alloy by N^{+} ion implantation.
2. Reconstruction of lattice structure of ion-implanted near-surface regions of HgCdTe epitaxial layers
3. Non-equilibrium phase composition of ZnNi alloys prepared by electrocrystallization
4. The role of radiation defects in HgCdTe epitaxial growth
5. HgCdMnZnTe: growth and physical properties
6. X-Ray diffraction studies of radiation defects in CdTe single crystals and epitaxial layers