Romanyuk Y. The influence of phonon-phonon interaction and Fermi resonance on Raman spectra of semiconductor crystals and nanostructures

The thesis is devoted to a theoretical and experimental study of the influence of phonon-phonon interaction and Fermi resonance on the Raman spectra in bulk and low-dimensional semiconductor structures. The theoretical model for describing of the experimental Raman spectra in Si/Ge superlattices with layers of Ge nanoislands was developed; it takes into account the real crystalline structure of both nanoislands and surrounding matrix, as well as interaction of their phonons. The influence of the phonon-phonon interaction and Fermi resonance on the features of Raman spectra of stressed silicon nanocrystals and crystals of quaternary compounds of Cu2ZnGeS4 have been studied. The theoretical model describing the experimental Raman spectra of mixed (MoS2/MoSe2) layered crystals and nanostructured films with different number of layers (n = 1-6), which takes into account the interlayer interaction and the influence of anharmonicity, was developed. The origin of the features in Raman spectra of hydroxylapatites in the region of OH-vibrations and their overtones were explained.