Excitons, photons, and phonons are elementary excitations that have been widely investigated in semiconductor systems. This thesis focuses on the exciton energy transfer between quantum dots, which is a physical process that involves all these elementary excitations. Exciton energy transfer is a common process in many artificial systems such as solar cells, lasers, and quantum gates.In order to study the exciton energy transfer, we develop a full quantum theory to describe the exciton-photon interaction and exciton-phonon interaction. We derive the exciton-photon interaction from the quantized field operator representing the electromagnetic field. In the derivation, the effect of a planar cavity, which modifies the photon density of states is considered. We also obtain the exciton-phonon interaction starting from the deformation potential. With both types of interaction given, we study the dynamics of the exciton transfer in a cavity by solving the Schrodinger equation for the coupled system of excitons, photons and phonons. Both elastic and inelastic exciton energy transfer are simulated. We find that the coupling to phonons enhances the exciton energy transfer when two dots are off-resonant. In addition to the theoretical and numerical study of the exciton energy transfer, two applications of the theory are discussed. As an application to quantum computing, phonon-assisted exciton energy transfer is proposed as the key ingredient in the implementation of a Quantum Zeno gate. In another application, we expand our approach to a multi-dot array, which can be applied to the design of novel light-harvesting devices.
Read
