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Twisted Moire Photonic Crystals: Their Nano-Fabrications, Optical Properties, and Applications in Light ExtractionAlnasser, Khadijah Saleh T. 05 1900 (has links)
In this dissertation, I report the results of my research on twisted moiré photonic crystals which can be formed through multi-beam holographic interference without a physical rotation and later fabricated by electron-beam lithography. Their optical properties, such as photonic bandgaps, multiple resonance modes, and quality factor are presented. Randomized moire photonic crystals in lattice are also studied. The applications of moire photonic crystals in improving light extraction efficiency are simulated and verified in light emitting devices. Furthermore, I simulated the light extraction efficiency in OLED when the Al layer is patterned with a triangular GPSC, square moiré PhC with defects in the uniform area, and random locations of the photonic lattice, and obtain light extraction efficiency of 78.9%, 79.9%, 81.7%, respectively. Also, the ratios of photoluminescence intensity of LED integrated with twisted moiré PhCs and random moiré PhCs over that without moiré PhCs are measured to be (1.3-1.9) and 1.74, respectively, in a good agreement with simulated ratios of 1.69 and 1.8.
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Fabrication and Characterization of Single-Crystal Diamond Photonic CavitiesLee, Jonathan Chaosung 19 September 2013 (has links)
Cavity quantum electrodynamics provide a platform to form a quantum network which connects individual quantum bits (qubits) via photon. Optical cavity, a device which traps photons in a confined volume can enhance the interaction between photons and the qubits serves as fundamental building block for a quantum network. Nitrogen vacancy (NV) centers in diamond has emerged as one of the leading solid-state qubits because of its long spin coherence time and single photon emission properties at room temperature. Diamond optical micro-cavities are highly sought after for coupling with NV centers. Fabrication of optical cavities from nano-crystalline diamond film has been demonstrated previously. The quality factor (Q) of such devices was limited by the material properties of the nano-crystalline diamond film. Fabrication of single-crystal diamond photonic cavities is challenging because there is no trivial way to form thin diamond film with optical isolation. In this thesis, we describe an approach to fabricate high quality single-crystal diamond optical cavities for coupling to NV centers in diamond. ingle-crystal diamond membranes were generated using an ion-slicing method. Whispering gallery modes were observed for the first time from microdisk cavities made from such material. However, the cavity Q (∼ 500) was limited by the ion damage created during processing. By using an homo-epitaxial overgrowth method, a high quality diamond film can be grown on the ion damaged membranes. Microdisk cavities with Q ∼ 3,000 were fabricated on these improved materials. Diamond membranes with a delta-doped layer of NV can be made using a slow overgrowth process which demonstrate the position and density of NV centers can be controlled in these membranes. Photonic crystal cavities with Q ∼ 4,000 were fabricated from the delta-doped membranes with cavity resonance near the zero phonon line of NV centers. Different color centers can also be introduced during the overgrowth process, and optical coupling of an ensemble of silicon vacancy centers is demonstrated by coupling to a diamond microdisk cavity. We believe the techniques developed in this thesis could contribute to building of a quantum photonic network using diamond as a platform. / Engineering and Applied Sciences
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High Performance Solar Cells Based on Perovskite Layers Prepared from Purified Precursor Materials / 高純度前駆体材料を用いて作製したペロブスカイト層に基づいた高性能太陽電池の開発Ozaki, Masashi 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21786号 / 工博第4603号 / 新制||工||1717(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 村田 靖次郎, 教授 辻 康之, 教授 小澤 文幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
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Contribution à la qualification et amélioration des moyens de production. Application à une usine de recherche et production de semi-conducteursBassetto, Samuel 06 1900 (has links) (PDF)
RESUME: La production industrielle de bien manufacturés permet, par une organisation et des actions adaptées, de toucher directement la qualité de milliers de produits. Cette thèse s'inscrit dans la logique d'amélioration de la qualité, par des actions sur les moyens de production. Elle est appliquée aux fabrications de circuits intégrés. Ces industries sont contraintes par un constant renouvellement des produits, des fortes rentabilités sur de très courtes périodes, une nécessité de produire en qualité et une exigence de rentabilité des moyens de recherche et production. Elles sont donc confrontées à des cycles d'apprentissage et de maîtrise de leurs moyens de production très courts, tout en maximisant la rentabilité. La recherche de la qualité est une priorité stratégique de ce secteur. Elle ne peut donc pas être uniquement décrétée, mais doit être opérationnelle et doit tenir compte des contraintes du domaine. Nous proposons pour cela un modèle en entreprise permettant de qualifier et d'améliorer les moyens de production de manière opérationnelle, dynamique tout en supportant les connaissances métier. Ce modèle est construit en intégrant les résultats de nos deux cas d'étude industriels. Cette thèse débute par une présentation du process control et de la problématique qui lui est associée. Le deuxième chapitre traite de la gestion des risques opérationnels. Le troisième traite de la mise sous contrôle des moyens généraux. Le modèle en entreprise est alors construit, au quatrième chapitre, en consolidant les résultats obtenus. L'application à d'autres horizons industriels clôture notre proposition.
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Förskollärares konstruktioner av vetenskaplig grund och beprövad erfarenhet / Preschool teachers' constructions of scientific basis and proven experiencePella, Thörnberg, Henriksson, Cecilia January 2021 (has links)
Syftet med studien är att bidra med kunskaper om vilka förståelser av vetenskaplig grund och beprövad erfarenhet som konstrueras i kommunikation mellan förskollärare. Studien styrs av två frågeställningar: Vilka språkliga kategorier konstrueras i förskollärares kommunikation om vetenskaplig grund? och Vilka språkliga kategorier konstrueras i förskollärares kommunikation om beprövad erfarenhet?. Studien har en kvalitativ metodansats, med en teoretisk utgångspunkt i kontextuell socialkonstruktionism. Studiens data samlas in genom två fokusgrupper med tio verksamma förskollärare i förskolan. Datan analyseras med hjälp av begreppen performativitet och fabrikationer. Performativiteten relateras till uppdraget i läroplanen och Skollag som förskollärare är ålagda att följa. I läroplanen för förskolan (Lpfö 18) står det att "undervisningen med innehåll och arbetsätt ska vila på vetenskaplig grund och beprövad erfarenhet". I studien synligörs fabrikationer som innebär att förskollärarna framställer eller rättfärdigar sin undervisning på ett bättre sätt än vad som överensstämmer med verkligheten. Studiens reslutat visar tre slutsatser: mångtydlighet, otydlighet i ansvar och brist på gemensam förståelse av begreppen vetenskaplig grund och beprövad erfarenhet. Begreppen har inte tidigare diskuterats av förskollärarna i studien, vilket innebär att egna tolkningar och förklaringar över begreppen uttalas. Förskollärarna saknar en tydligare definition av vetenskaplig grund och beprövad erfarnehet, vilket överensstämmer med vad tidigare forskning belyser. / The Purpose of the study is to contribute knowledge about which understandings of scientific basis and proven experience are constructed in communication between preschool teachers. The study is guided by two questions: What language categories are constructed in preschool teachers' communications about the scientific basis? and What language categories are constructed in preschool teachers' communication about proven experience?. The study has a qualitative methodological approach, with a theoretical starting point in contextual social constructionism. The study data is collected through two focus groups with ten active preschool teachers in the preschool. The data are analyzed to the concepts of performativity and fabrications. The performativity is related to the assignment in the curriculum for preschool (Lpfö 18) states that "teaching with content and working methods must be based on scientific grounds and proven experience". The study highlights fabrications that mean that preschool teachers present or justify their teaching in a better way than what corresponds to reality. The results of the study show three conclusions: ambiguity, ambiguity in responsibility and lack of common understanding of the concepts of scientific basis and proven experience. The concepts have not previously been discussed by the preschool teachers in the study, which means that their own interpretations and explanations of the concepts are pronounced. Preschool teachers lack a clearer definition of scientific basis and proven experience, which is in line with what previours research sheds light on.
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