A bound polaron in a spherical quantum dot with a finite confining potential

The bound polaron in a spherical quantum dot with a finite confining potential (the barrier radius R-2 is far larger than the well radius R-1, R-1 much less than R-2) has been theoretically investigated. Before studying the polaronic effect, we have deduced the phonon modes in the system within the framework of the dielectric continuum model. The confined longitudinal optical (LO) phonon in both in the well materials (LO1) and in the barrier materials (LO2) and the interface optical (10) phonon modes, as well as the corresponding electron-phonon interaction Hamiltonians, were derived. Numerical calculations for a ZnSe/CdSe spherical quantum dot reveal that the electron-phonon interaction can greatly modify the impurity binding energy. The LO1 modes play a major role in the modification. The influence of LO2 modes on the impurity binding energy can not be neglected when the well is relatively narrow. The contribution of the IO phonons is null for the central impurity, and has a maximum when the impurity shifts from the center to the edge of the well when R-1 is keept unchanged. Furthermore, its influence is small and can be neglected.