Optical nonlinearities of InP/ZnS core/shell and inverted core/shell quantum dot

Exciton binding energies as a function of core/shell radius ratio are studied for the InP/ZnS core/shell quantum dot and ZnS/InP inverted core/shell quantum dot theoretically. The self-interaction potential due to the interaction between the exciton and its image charge and the built-in internal fields between inner and outer core materials are included in the Hamiltonian. The optical nonlinear susceptibilities for the second-harmonic generation and the third-harmonic generation with the photon energy for a constant radius are obtained for the core/shell and inverted core/shell quantum dots. The third-order Kerr effect as a function of photon energy is found for core/shell and inverted core/shell quantum dots of InP/ZnS and ZnS/InP semiconductors, respectively. The Kerr effect is studied using the real part of the third-order optical susceptibility.