Raman scattering by carbon nanotubes coupled to quantum dots via dipolar excitonic interaction

Abstract

The dipole-dipole interactions between excitons are of paramount importance in the nanoscale structures. When two excitons are placed together they can exchange the energy can manifest in the resonant Raman cross sections. We provide theoretical framework for such effects by combining the coupled oscillator model and perturbation theory. We apply this theory to a hybrid film comprising semiconducting quantum dots and metallic carbon nanotubes. The quantum dots exciton has a fixed energy, while the nanotube resonances span across a larger range from 1.7 to \SI{1.93}{eV}. We acquire the resonant Raman profiles of the pristine nanotubes and hybrids and find a relative shift between them. The shift direction depends on the relative energies between the CNT and QD exciton energies, as predicted by our theory.