Hydrogenic impurity bound polaron in a quantum dot quantum well structure

A variational approach is used within the framework of effective mass approximation to study the binding energy of the hydrogenic impurity in a spherical quantum dot quantum well (QDQW) structure. The electron-and ion-longitudinal-optical (LO) phonon interactions are taken into account in the calculation. The numerical results for the CdS/HgS QDQW structure embedded in an insulator matrix show that the binding energy is sensitive both to the size of the core and the width of the shell. The binding energy decreases with the core radius being increased, and exhibits a maximum with the shell width being increased. The LO phonon effect lowers the binding energy of the on-center impurity and decreases sharply with the shell well-width being increased.