Electron-phonon interaction and its effects on electronic properties in quantum confined systems

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(1) Polaron effects on an exciton in quantum well with an infinite potential barrier and a finite one are calculated and discussed. Role of the bulk-type and the interface-type phonon changes according to the large to small well width, which reflects the dimensional character of an exciton.(2) LO phonons and electron-LO phonon interaction in mixed polar crystals are formulated. Self-energy shift and effetvie mass correction are calculated. Also LO phonons (bulk and interface type) and electron-LO phonon interaction in quantum well consisting of mixed polar crystals are formulated and are shown to be divided into three types according to whether the well or the barrier is made of mixed crystals. Polaron energy shifts are calculated in various systems. Moreover polaron effects on exciton in quantum well consisting of mixed polar crystals are calculated and are discussed in relation to the well-width dependence and the contribution of the various LO phonon modes on properties such as exci … More ton-LO phonon interaction and exciton polaron energy shift. Specially the method is applied to the interesting quantum well systems consisting of mixed polar crystals with the use of qallium nitride or zinc compounds.(3)Effects of LO phonons (bulk and interface type) for an electron, confined in a spherical quantum dot embedded in a nonpolar matrix are studied theoretically. The variational method is developed to provide the results, being valid for the wide range of the dot radius and the electron-LO phonon coupling strength. Also the size dependence of polaron effects on an exciton in a spherical quantum dot is studied by using a variational method. Exciton energy, exciton-phonon interaction energy and the virtual phonon number are calculated. It is clearly shown that polaron effects on an exciton vanish in the limit of the small quantum dot.(4)CuCl microcrystals embedded in an SiOィイD22ィエD2 matrix is prepared by an novel RF-magnetoron sputtering combined with an inductively coupled plasma. Optical properties (absorption and luminescence spectra) of the exciton and the biexciton in the system are investigated. In the luminescence spectra intensities of the exciton and the biexciton have linear and superlinear dependencies, respectively. Less