Energy absorption of an exciton-biexciton system in a quantum dot – Metal nanoparticle hybrid

Abstract

We study theoretically the energy absorption rate spectrum of a coupled nanostructure composed of a semiconductor quantum dot (SQD) and a spherical metal nanoparticle (MNP) interacting with a linearly polarized electromagnetic field. A three-level ladder-type energy level scheme is used for the description of the SQD, where exciton and biexciton transitions are accounted for. We investigate the impact due to the modification of the values of a series of physical parameters on the energy absorption rate spectrum, including the intensity and the polarization direction of the applied field, the biexciton energy shift, the interparticle distance and multipole effects. We find three regular, almost Lorentzian-shaped, peaks on the SQD spectrum and three Fano-type resonance line shapes on the MNP spectrum and show that the distance between them increases with the increase of the absolute value of the biexciton energy shift. The results have potential applications in nanotechnology.