ISBN 9783843956291

978-3-8439-5629-1, Reihe Physik

Julian Maisch
Study of a single-electron excitation approach and an open cavity concept for quantum dot single-photon sources

205 Seiten, Dissertation Universität Stuttgart (2024), Softcover, A5

Zusammenfassung / Abstract

Within the emerging quantum technologies, single-photon sources play a crucial role in order to create photons as so-called `flying qubits'. One promising platform are InAs/GaAs quantum dots (QDs) which have been studied in the last decades. However, the technological applications pose special challenges regarding the fundamental emission properties, pumping schemes or the emission wavelength. In this work, two main topics are covered: For one, electrically pumped sources based on a novel envisioned device combining single-electron transport and single-photon emission. Secondly, QDs emitting in the telecom O-band which are integrated in an open fiber-cavity. Both topics represent a technological impact.

The first part of the thesis presents several steps towards a combined single-electron single-photon device. Even though the envisioned device have not could been realized, several prerequisites regarding the limitations of the QD structure were studied. Specifically, the QDs in close distance to the surface and a p-doped layer were investigated. Furthermore, a novel QD structure with electron and hole blocking layers was introduced and precharacterized.

In the second part, an open-fiber cavity was successfully realized and a thorough study of all parameters was conducted. Specifically, the QD properties were compared inside and outside in order to quantify the Purcell enhancement. The results are supported by a full theoretical description of the system both in the `bad cavity'- and the `bad emitter'-regime.