Contrôle des propriétés quantiques de fluorescence des nanocristaux semi-conducteurs

Abstract : This thesis focuses on the characterization of nanocrystals whose structure allows to drastically reduce their blinking. The main property of these CdSe nanocrystals is that they are covered by a thick shell of CdS which preserves them from interactions with the surroundings. The realization of a very thick shell is at the origin of the suppression of the long low emitting periods. In addition, we found that if the hole is still blocked into the core of the nanocrystal, the electron is delocalized into the whole structure. This effect causes a reduction of the efficiency of Auger processes. At low pumping rates, this implies that the nanocrystals do not any more exhibit real off periods. This result, combined with measurements of lifetime corresponding to periods of extinction and emission, enabled us to calculate recombination rates of the various processes involved in a low excited nanocristal, whether it is neutral or ionized. At stronger pumping rates, we show the possibility to observe radiative cascades due to multiexcitonic recombinations. The last part of the thesis concerns preliminary results we obtained controlling the emission of nanocrystals by coupling it with a Bragg mirrors photonic cavity. We observed the emission of single photons and we demonstrated the effect of the cavity on the radiative lifetime of individual nanocrystals.
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Theses
Physique [physics]. Université Paris-Diderot - Paris VII, 2009. Français
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Submitted on : Monday, December 14, 2009 - 12:43:02 PM
Last modification on : Thursday, November 22, 2018 - 2:39:54 PM
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  • HAL Id : tel-00440992, version 1

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Piernicola Spinicelli. Contrôle des propriétés quantiques de fluorescence des nanocristaux semi-conducteurs. Physique [physics]. Université Paris-Diderot - Paris VII, 2009. Français. 〈tel-00440992〉

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