Self-assembly of quantum dots and rings by droplet epitaxy and their optical properties

Developments in the self-assembly by droplet epitaxy in our research group have enabled us to fabricate various GaAs quantum nanostructures of high optical quality such as quantum dots, single quantum rings, and concentric double quantum rings. We clarified their electronic states and relaxation processes by micro photoluminescence experiments. We achieved lasing of lattice-matched GaAs quantum dots and their excitonic Rabi oscillation by resonant excitation. We succeeded in the control of their photon emission rate by photonic crystal micro cavities.