Donor-impurity-related optical absorption and refractive index changes in GaAs/AlGaAs core/shell spherical quantum dots

In this study, the linear and nonlinear intersubband optical absorption coefficients (OACs) and refractive index changes (RICs) in GaAs/AlGaAs core/shell spherical quantum dots (QDs) are theoretically investigated within the framework of the compact-density-matrix approach and iterative method for both cases with and without on-center impurity. The energy eigenvalues and their corresponding eigenfunctions of the system are calculated by using the differential method. Our results show that the position and the magnitude of the resonant peaks of the nonlinear OACs and RICs depend strongly on the hydrogenic impurity and QDs radius. It was found that the total OACs indicates saturation at sufficiently high incident intensities. Also we found that the binding energy of the ground and excited states of the impurity depend on the QDs radius.