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Sebastian Moehl

Study of optical properties of II-VI semiconductor quantum dots for their application in high-temperature single-photon emission

Published on 23 September 2005


Thesis presented September 23, 2005

Abstract:
We studied the optical properties of single CdSe and CdTe quantum dots with the objective of using them as sources that can emit single photons at high temperatures (beyond 100 K). So we characterized the origins of dephasing (random charge fluctuations, exciton-phonon interaction) that limit the emission of indistinguishable photons. The study of our charged CdSe dots allows to show the importance of the mixing between heavy holes and light holes that limits the usage of the dots as sources of pairs of entangled photons. Moreover, we studied two inter-dot transfer mechanisms that affect the emission of single photons on demand: the transfer by tunneling, occurring at high dot densities, and the thermoactivated transfer that appears at low carrier confinements. Finally, the proof of single photon emission is furnished by means of photon correlation experiments with a continuous wave excitation.

Keywords:
single photon emitter, quantum dots, II-VI semiconductors, Purcell effect

On-line thesis.