Dokument: Electron capture and emission dynamics of self-assembled quantum dots
| Titel: | Electron capture and emission dynamics of self-assembled quantum dots | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=58897 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20220225-091406-8 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | M.Sc. Schnorr, Laurin Maximilian [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Heinzel, Thomas [Gutachter] Prof. Dr. Egger, Reinhold [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 530 Physik | |||||||
| Beschreibung: | This thesis is concerned with the study of electron capture and emission dynamics of InAs self-assembled quantum dots (SAQDs) that are embedded into a Schottky diode structure grown by molecular beam epitaxy. SAQDs are small islands of semiconducting material in which charge carriers can only occupy a discrete density of states. The charge state of the SAQDs is measured via the capacitance of the Schottky diode. A sudden change in the applied voltage causes the SAQDs to either emit or capture electrons, the time dependence of which is analyzed using Deep Level Transient Spectroscopy (DLTS) and Laplace DLTS (LDLTS) at different temperatures.
The goal of this thesis is to electronically measure the charge transfer dynamics of SAQDs in doped sample structures with large distances (> 100 nm) between the quantum dots and the electrodes, as commonly found in optoelectronic devices. Measurements are conducted under experimental conditions that have been carefully avoided before, where assumptions about the dominance of a single charge transfer process can no longer be justified. First, the implementation of the inverse Laplace transform algorithm and the details of its application to realistic measurement data is described. Subsequently, temperature and voltage dependent measurements of the electron emission are analyzed via LDLTS and compared to results of other established methods. Furthermore, the capture rates are measured as a function of the applied bias voltage at T = 7 K and T = 77 K, where the interplay between the capture and emission dynamics could be observed and modeled quantitatively. The model allows for the extrapolation of the steady state electron occupancy of the SAQDs which is found to be orders of magnitude larger than the electron distribution in the bulk material, indicating an additional electron source filling the SAQDs. The hysteretic capacitance-voltage (CV) behavior that has previously only been explained qualitatively could be quantitatively predicted without modification to the model, and features in the CV trace could be unambiguously related to the sample and SAQD properties. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Physik » Physik der kondensierten Materie | |||||||
| Dokument erstellt am: | 25.02.2022 | |||||||
| Dateien geändert am: | 25.02.2022 | |||||||
| Promotionsantrag am: | 21.12.2021 | |||||||
| Datum der Promotion: | 17.02.2022 |
