Our work is devoted to the study of the optical and vibrational properties of semiconductor and metallic nanostructures. The inelastic light scattering by low frequency acoustic vibrations (few meV), named Raman-Brillouin scattering, gives access to such properties. On one hand, due to their size, the electronic states of semiconductor nanostructures (e.g. quantum wells, nanowire or quantum dots) are confined and discretized. These electronic states are involved in the Raman-Brillouin scattering and act as an intermediary during the optical process. On the other hand, when applying an external electric field, metallic nano-objects sustain collective oscillation modes of the free electron gas called surface plasmons. In the Raman-Brillouin scattering, these surface plasmon modes also act as an intermediary during the emission and the absorption of low frequency acoustic vibrations. The understanding of the interaction between the acoustic vibrations and the electronic excitations, whether they are excitons (confined electronic states in semiconductors) or surface plasmons (in metals), gives direct information on the optical and vibrational properties of those nano-objects.
Doctoral thesis of Nicolas Large