Slobodian M. Influence of three-dimensional ordering and deformations on X-ray diffraction in real multilayered structures

The thesis is devoted to the research of the structure and basic physical properties of InGaAs/GaAs multilayers with quantum dots (QDs), depending on the growth conditions and external influences, by means of high-resolution Х-ray diffractometry. The method of reciprocal space mapping was adapted to solve the inverse problem of determination of the composition and elastic deformations in the self-ordered QDs systems. For the first time the nature of superlattice (SL) period change under rapid thermal treatment was observed and explained. The effect was given by macrobent influence on the angular positions of SL coherent satellites. The nature of reflection curves sensitivity to the macrobent of multilayer system was determined, which lies in the displacements of coherent satellites from their Bragg positions. The effect of coherent satellites splitting and lateral satellites inclination for the superlattices with quantum dots was observed and explained. It lies in the vertical and inclined inheritanceof QDs and quantum wires (QWs) during their growth. For the first time the technique of QDs spatial lattice reconstruction from experimental reciprocal space maps was proposed. X-ray diffraction measurements revealed the peculiarities of self-directional ordering of QWs under the different As molecular fluxes used in technological processes. The differ-ence of adatoms embedding mechanisms for As2 and As4 fluxes determines the considerable difference in the processes of surface diffusion and the formation of the elastic de-formation fields in epitaxial structures. The influence of rapid thermal annealing on the structural reconstruction of QDs arrays in multilayer InGaAs/GaAs structures was investigated. The thermal stability interval of multilayers structural characteristics was determined and the model of thermal transforma-tions inside the structure was built. The nature of 2D-3D structural transitions was explained.