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Yoanna-Reine Nowicki-Bringuier

Novel geometries of optical confinement for the control of semiconductor quantum dots' spontaneous emission

Published on 13 June 2008


Thesis presented June 13, 2008

Abstract:
The aim of this ph-D thesis was to study by spectrophotometry coupling phenomenon between single emitters such as InAs/GaAs quantum dots inside an optical microcavity tailored to the emitter. The purpose was to propose and to demonstrate the potential of several microcavities' original geometries. In this manuscript, we will start from the growth's description of such structures by Molecular Beam Epitaxy (MBE) to focus on three different proposals of innovative geometries for which we will both describe the technological process leading to their manufacturing, as well as the optical studies performed to demonstrate their potential. For example, microdisks directly bonded to sapphire showed very interesting thermal dissipation leading to amazing properties for microlasers. On Bragg mirrors micropillars, we have shown for the first time that those structures were able to sustain both high-Q whispering-gallery modes and lateral standard micropillars modes, as well as the ability to use those modes as lasing modes, which open new possibilities in term of microphotonic devices. We also developed a specific reproducible Au-coating technique and studied its effect on the micropillars modes, showing that no degradation of the optical properties of the pillar due to the metal occurred, leading to the possibility to use this technique for various specific applications. Finally, we propose and demonstrate the potential of using a single quantum dot inserted in a monolithic nanowire for its very high collection efficiency, showing that this kind of structure could be a very serious competitor to the usual geometry used for single photon sources, the micropillar.

Keywords:
microcavity, quantum dots, Purcell effect, Infra-red Spectrophotometry, Molecular Beam Epitaxy, nanowires, InAs/GaAs/ microphotoluminescence

On-line thesis.