Vuychik M. Photoluminescence and Raman scattering in self-assembled nanoislands CdSe/ZnSe structures

Dissertation is devoted to the research of structural and composition properties of the CdSe/ZnSe structures with self-inducted nanoislands grown by the method of molecular-beam epitaxy. It is shown, that spectral position of the maximum of photoluminescence is determined by the interdiffusion effect of Cd and Zn in the region of insertion and depends on the nominal thickness of the insertion. Inhomogeneous broadening form of radiation band is conditioned by simultaneous contribution of the two-dimensional CdxZn1-xSe layer and local inclusions with Cd-rich islands to the photoluminescence spectrum. It is found, that the form and position of a defect radiation band of nanostructures depends on the temperature of measuring and energy of excitation, that it is conditioned by the localization of structural defects in different parts of heterostructure. The antistokes photoluminescence of CdSe/ZnSe nanostructures it is observed and investigated for the first time. The mechanism of its excitation is accounted for on the basis of the model of two-step process of excitation through the real intermediate deep energy levels. It is shown, that at resonance excitation the form of radiation band of CdSe/ZnSe nanostructure is determined by the strong coupling of localized excitons with optical phonons in the insertion. Results are interpreted in framework of the models of exciton edge of mobility.