Thesis presented October 24, 2005

Abstract:
In this work, CdSe/ZnSe semiconductor quantum dots are grown by molecular beam epitaxy and placed into pillar microcavities to control their spontaneous emission. When an emitting dipole is located in a small volume optical cavity and resonant with a cavity mode, its radiative lifetime can be strongly reduced: this is the Purcell effect.
We first present a new method for growing self-assembled CdSe/ZnSe quantum dots. Structural characterizations by Atomic Force Microscopy, Transmission Electron Microscopy and High Resolution X-Ray Diffraction are presented. Optical studies performed on a large assembly of quantum dots or on a single quantum dot allow us to characterize the confinement of the carriers into the quantum dots as well as the thermal activation of the non-radiative deexcitation channels. Finally, those quantum dots are located into micropillars to control their spontaneous emission. The microcavities are elaborated using oxide deposition for the Bragg mirrors and CdSe/ZnSe quantum dots as active media. Time-resolved photoluminescence measurements on a series of single quantum dots probe the Purcell effect. A three-fold enhancement of quantum dot spontaneous emission rate is observed for quantum dots in resonance with excited degenerated modes of the pillar.

Keywords:
II-VI semiconductors, molecular beam epitaxy, Purcell effect, microcavities, quantum dots

On-line thesis.