Дисертації з теми "Quantum material"
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Zietal, Robert J. "Quantum elecrodynamics near material boundaries." Thesis, University of Sussex, 2010. http://sro.sussex.ac.uk/id/eprint/2520/.
Повний текст джерелаMatloob, Mohammad Reza. "Theory of electromagnetic field quantization in material media." Thesis, University of Essex, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282572.
Повний текст джерелаWang, Qi. "Study of InGaN based quantum dot material and devices." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522509.
Повний текст джерелаWong, Huei Ching. "Investigation of quantum dot based material systems for metro-access network." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437270.
Повний текст джерелаBlay, Claire. "Characterisation of intermixed quantum well material by measurements of spontaneous emission." Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323571.
Повний текст джерелаBRUNI, FRANCESCO. "NOVEL MATERIAL DESIGN AND MANIPULATION STRATEGIES FOR ADVANCED OPTOELECTRONIC APPLICATIONS." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/151660.
Повний текст джерелаMy PhD has been focused on organic semiconductors for photovoltaics and photodetecting applications. Initially, I worked on the control of the morphology in binary blends of small organic molecules and fullerenes using the so called latent pigment approach. Subsequently, I investigated the charge accumulation and polarization effect occurring at the interface between water and a polymeric semiconductor used as optical component in retinal prosthesis by means of inorganic colloidal nanocrystals featuring a ratiometric sensing ability for electron withdrawing agents. As a last part of the work, I focalized on the applications of these nanocrystals as ratiometric sensors for intracellular pH probing and pressure optical monitoring. Specifically, during the first part of my PhD, I worked in the field of organic photovoltaics on the morphology engineering of the active layer of small molecules bulk-heterojunction solar cells. I demonstrated a new strategy to fine tune the phase-segregation in thin films of a suitably functionalized electron donor blended with fullerene derivatives by introducing in the system a post-deposition thermally activated network of hydrogen bonds that leads to improved stability and high crystallinity. Moreover, this process increases the carrier mobility of the donor species and allows for controlling the size of segregated domains resulting in an improved efficiency of the photovoltaic devices. This work revealed the great potential of the latent hydrogen bonding strategy that I subsequently exploited to fabricate nanometric semiconductive features on the film surface by using a very simple maskless lithographic technique. To do so, I focalized a UV laser into a confocal microscope and used the objective as a “brush” to thermically induce a localized hydrogen bonding driven crystallization with diffraction limited resolution. My work on organic semiconductors continued with a study on the surface polarization driven charge separation at the P3HT/water interfaces in optoelectronic devices for biologic applications. In this work, I probed the local accumulation of positive charges on the P3HT surface in aqueous environment by exploiting the ratiometric sensing capabilities of particular engineered core/shell heterostuctures called dot-in-bulk nanocrystals (DiB-NCs). These structures feature two-colour emission due to the simultaneous recombination of their core and shell localized excitons. Importantly, the two emissions are differently affected by the external chemical environment, making DiB-NCs ideal optical ratiometric sensors. In the second part of my PhD, I, therefore, focalized on the single particle sensing application of DiB-NCs. Specifically, I used them to ratiometrically probe intracellular pH in living cells. With this aim, I studied their ratiometric response in solution by titration with an acid and a base. Subsequently, I internalized them into living human embryonic kidney (HEK) cells and monitored an externally induced alteration of the intracellular pH. Importantly, viability test on DiB-NCs revealed no cytotoxicity demonstrating their great potential as ratiometric pH probes for biologic application. Finally, I used DiB-NCs as a proof-of-concept single particle ratiometric pressure sensitive paint (r-PSP). In this application, the emission ratio between the core and the shell emission is used to determine the oxygen partial pressure and therefore the atmospheric pressure of the NC environment.
Rasin, Ahmed Tasnim. "High efficiency quantum dot-sensitised solar cells by material science and device architecture." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/78822/1/Ahmed%20Tasnim_Rasin_Thesis.pdf.
Повний текст джерелаPillar-Little, Timothy J. Jr. "CARBON QUANTUM DOTS: BRIDGING THE GAP BETWEEN CHEMICAL STRUCTURE AND MATERIAL PROPERTIES." UKnowledge, 2018. https://uknowledge.uky.edu/chemistry_etds/94.
Повний текст джерелаHatami, Soheil, Christian Würth, Martin Kaiser, Susanne Leubner, Stefanie Gabriel, Lydia Bahrig, Vladimir Lesnyak та ін. "Absolute photoluminescence quantum yields of IR26 and IR-emissive Cd₁₋ₓHgₓTe and PbS quantum dots: method- and material-inherent challenges". Royal Society of Chemistry, 2015. https://tud.qucosa.de/id/qucosa%3A36307.
Повний текст джерелаStavrinou, Paul Nicholas. "A study of InP-based strained layer heterostructures." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261711.
Повний текст джерелаYong, Jennifer Chai Lin. "Investigation of quantum well material systems for 1300nm wavelength high-speed uncooled lasers." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399933.
Повний текст джерелаFarrokhi, M. Javad. "ELECTRONIC PROPERTIES OF ATOMICALLY THIN MATERIAL HETEROSTRUCTURES." UKnowledge, 2019. https://uknowledge.uky.edu/physastron_etds/67.
Повний текст джерелаMoreira, Manuel Viotr A. "Fabrication and characterisation of surface grating DFB lasers using AlGaAs/GaAs quantum well material." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361730.
Повний текст джерелаYoung, Amber Lynn. "Characterization of Immobilized Aqueous Quantum Dots: Efforts in High-Resolution Microscopy." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145169.
Повний текст джерелаMenzel, Jan Philipp. "Wavelength-dependent photoreactivity for macromolecular material design." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/210196/1/Jan%20Philipp_Menzel_Thesis.pdf.
Повний текст джерелаIyengar, Ananth Shalvapulle. "Synthesis and characterization of micro/nano material for thermoelectric applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1276182370.
Повний текст джерелаLaskin, Gennadii [Verfasser], and Jochen [Akademischer Betreuer] Mannhart. "Fabrication and analysis of nanostructures in the quantum material SrRuO3 / Gennadii Laskin ; Betreuer: Jochen Mannhart." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2019. http://d-nb.info/1201646308/34.
Повний текст джерелаHöglund, Linda. "Growth and characterisation of InGaAs-based quantum dots-in-a-well infrared photodetectors." Doctoral thesis, Linköpings universitet, Materiefysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15774.
Повний текст джерелаOn the day of the defence date the status on article IV was: Accepted.
Souza, de Almeida Jailton. "Designing and Tuning the Properties of Materials by Quantum Mechanical Calculations." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6923.
Повний текст джерелаAkram, Nadeem. "Photonic devices with MQW active material and waveguide gratings : modelling and characterisation." Doctoral thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-433.
Повний текст джерелаQC 20100827
Wigblad, Dan. "Structural and optical characterization of Si/Ge quantum dots." Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11672.
Повний текст джерелаIn this study silicon-germanium quantum dots grown on silicon have been investigated. The aim of the work was to find quantum dots suitable for use as a thermistor material. The quantum dots were produced at KTH, Stockholm, using a RPCVD reactor that is designed for industrial production.
The techniques used to study the quantum dots were: HRSEM, AFM, HRXRD, FTPL, and Raman spectroscopy. Quantum dots have been produced in single and multilayer structures.
As a result of this work a multilayer structure with 5 layers of quantum dots was produced with a theoretical temperature coefficient of resistance of 4.1 %/K.
Peli, S. "UNFOLDING THE ULTRAFAST INTERPLAY BETWEEN DELOCALIZED WAVEFUNCTIONS AND LOCALIZED ELECTRONIC INTERACTIONS IN QUANTUM CORRELATED MATERIALS." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/259322.
Повний текст джерелаZafarullah, Ijaz. "Thulium ions in a yttrium aluminum garnet host for quantum computing applications material analysis and single qubit operations /." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/zafarullah/ZafarullahI0508.pdf.
Повний текст джерелаFrisk, Andreas. "Growth and characterization of Ge quantum dots on SiGe-based multilayer structures." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16674.
Повний текст джерелаThermistor material can be used to fabricate un-cooled IR detectors their figure of merit is the Temperature Coefficient of Resistance (TCR). Ge dots in Si can act as a thermistor material and they have a theoretical TCR higher than for SiGe layers but they suffer from intermixing of Si into the Ge dots. Ge dots were grown on unstrained or strained Si layers and relaxed or strained SiGe layers at temperatures of 550 and 600°C by reduced pressure chemical vapor deposition (RPCVD). Both single and multilayer structures where grown and characterized. To achieve a strong signal in a thermal detector a uniform shape and size distribution of the dots is desired. In this thesis work, an endeavor has been to grow uniform Ge dots with small standard deviation of their size. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) have been used to characterize the size and shape distribution of Ge dots. Ge contents measured with Raman spectroscopy are higher at lower growth temperatures. Simulation of TCR for the most uniform sample grown at 600°C give 4.43%/K compared to 3.85%/K for samples grown at 650°C in a previous thesis work.
Strained surfaces increases dot sizes and make dots align in crosshatched pattern resulting in smaller density, this effect increases with increasing strain.
Strain from buried layers of Ge dots in a multilayer structure make dots align vertically. This alignment of Ge dots was very sensitive to the thickness of the Si barrier layer. The diameter of dots increase for each period in a multilayer structure. When dots are capped by a Si layer at the temperature of 600°C intermixing of Si into the Ge dot occurs and the dot height decrease.
Pal, Singh Amrit [Verfasser], and Roman [Akademischer Betreuer] Schnabel. "Intensity-dependent phase shifts in optical materials for quantum state preparation and absorption measurements in thin film coatings and bulk material / Amrit Pal Singh ; Betreuer: Roman Schnabel." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2018. http://d-nb.info/1161530266/34.
Повний текст джерелаYang, Hung-Yu. "Novel Electromagnetic Responses in Topological Semimetals: Case Studies of Rare-Earth Monopnictides and RAlX Material Family." Thesis, Boston College, 2021. http://hdl.handle.net/2345/bc-ir:109188.
Повний текст джерелаSince the idea of topology was realized in real materials, the hunt is on for new candidates of topological semimetals with novel electromagnetic responses. For example, topological states can be highly conductive due to a topological protection, which can be destroyed in a magnetic field and lead to an extremely high magnetoresistance. In Weyl semimetals, a transverse current that would usually require a magnetic field to emerge, can be generated by intrinsic Berry curvature without a magnetic field -- the celebrated anomalous Hall effect. In this dissertation, both phenomena mentioned above are studied in rare-earth monopnictides and RAlX material family (R=rare-earths, X=Ge/Si), respectively. The monopnictides are ideal for the study of extreme magnetoresistance because of their topological transitions and abundant magnetic phases. In LaAs, we untied the connection between topological states and the extreme magnetoresistance, the origin of which is clarified. In HoBi, we found an unusual onset of extreme magnetoresistance controlled by a magnetic phase dome. On the other hand, RAlX material family is a new class of Weyl semimetals breaking both inversion and time-reversal symmetries. In particular, in PrAlGeₓSi₁₋ₓ (x=0-1), we unveiled the first transition from intrinsic to extrinsic anomalous Hall effect in ferromagnetic Weyl semimetals, and the role of topology is discussed. In CeAlSi, we found that the Fermi level can be tuned as close as 1 meV away from the Weyl nodes; moreover, a novel anomalous Hall response appears only when the Fermi level is tuned to be near the Weyl nodes. Thus, we established a new transport response solely induced by Weyl nodes
Thesis (PhD) — Boston College, 2021
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
Ji, Botao. "Synthèse et propriétés optiques de quantum dots fluorescents plasmoniques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://pastel.archives-ouvertes.fr/pastel-01065068.
Повний текст джерелаWingen, Georg. "Vertikale Wanderwellenmodulatoren auf Quantenfilmbasis für die optische Informationsverarbeitung - Vertical travelling-wave modulators using quantum-well material for optical information processing." Gerhard-Mercator-Universitaet Duisburg, 2001. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-10122001-113233/.
Повний текст джерелаSilva, Carlos Jacinto da. "Caracterização termo-óptica de materiais lasers usando a técnica de lente térmica." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-09042008-094626/.
Повний текст джерелаIn this work we investigate the thermal properties (diffusivity, conductivity, temperature coefficient of the optical path length change, etc) and loss processes owing to ion-ion interactions in laser glassy and crystalline materials. Since the fluorescence quantum efficiency, , is directly related to these mechanisms that lead to luminescence quenching, the studies were performed mainly observing the effects of these processes on . Thermal lens (TL) spectra were used to determine , energy transfer efficiency between matrix-ion, and to analyze effects of \"dead site\" on . A new method based on the TL technique was proposed to determine q and the temperature coefficient of the optical path length change. This new approach was used to investigate concentration quenching mechanisms in glassy materials. It was also used to study effects of OH radicals and other impurities in Yb3+ doped phosphate glasses. Upconversion Auger processes, which are very important for high power laser systems, were investigated in Nd3+ -doped glasses and crystals. In glasses the study was performed as a function of doping ions. In this study the TL showed to be very sensitive, presenting results with uncertainties much smaller than previous literatures. Following the study of losses, we investigate light induced optical distortion as a function of temperature, excitation power, and polarization in SNB ferroelectric crystal. Using the TL technique, the thermal properties through the phase transition ferroelectric-paraelectric in SBN crystals were investigated. In addition, this thesis significantly contributes for characterization of laser materials with potential applications, considering that severa1 of the loss mechanisms studied here must be considered in laser design. This work also presents the TL technique as a valuable to01 for the present study.
Diac, Andreea Petronela. "Design, synthesis and supramolecular architectures of new heterocyclic compounds with potential applications in material chemistry and photovoltaic conversion." Thesis, Angers, 2015. http://www.theses.fr/2015ANGE0019/document.
Повний текст джерелаThe thesis entitled “Design, Synthesis and SupramolecularArchitectures of New Heterocyclic Compounds with PotentialApplications in Material Chemistry and Photovoltaic Conversion” isstructured into five chapters concerning new: a) heterocycliccyclopenta[c]pyrans; b) indenopyrone derivatives with fluorescentproperties; c) potential devices of molecular electronics; d)donors for organic photovoltaics and e) electroluminescent carbon‘quantum’ dots.The first chapter presents a study of pseudoazulenederivatives having a cyclopenta[c]pyran unit. The survey comprises thesynthesis, structural analysis and reactivity towards electrophilicsubstitution in order to obtain fluorescent compounds.The second chapter deals with the separation odiastereoisomers and the study of fluorescent propertiesindenopyrone derivatives.The third chapter describes the synthesis of newarchitectures based on cyclopenta[c]pyran unit that can be structurallymodified by the influence of a chemical or electrochemical stimulus inorder to work as potential devices in molecular electronics.In the fourth chapter, the synthesis andelectronic properties of new molecular donors for organic solar cellswas described.The fifth and last chapter outlines the passivation of surfacedefects on carbon nanoparticles using small organic molecules orpolymers in order to obtain photoluminescent carbon nanoparticlesdubbed as carbon‘quantum’dots
Schober, Giulio Albert Heinrich [Verfasser], and Manfred [Akademischer Betreuer] Salmhofer. "Quantum Field Theory of Material Properties: Its Application to Models of Rashba Spin Splitting / Giulio Albert Heinrich Schober ; Betreuer: Manfred Salmhofer." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/1180738195/34.
Повний текст джерелаZhang, Kuanshou. "Intracavity optical nonlinear devices using X(2) quasi-phase-matched material : classical and quantum properties and application to all-optical regeneration." Paris 6, 2002. http://www.theses.fr/2002PA066553.
Повний текст джерелаKhatib, Maher Al. "EPR Spectroscopy for the investigation of materials of technological and industrial interest." Doctoral thesis, Università di Siena, 2019. http://hdl.handle.net/11365/1070360.
Повний текст джерелаDoñate, Buendía Carlos. "Synthesis of nanomaterials by high throughput pulsed-laser based systems: Application in biomedicine and material processing." Doctoral thesis, Universitat Jaume I, 2019. http://hdl.handle.net/10803/668339.
Повний текст джерелаEl trabajo desarrollado en esta tesis se basa en el estudio de sistemas de generación de nanopartículas en líquidos mediante láser pulsado, mejorando su producción y empleando los nanomateriales generados en aplicaciones como imagen biomédica o additive manufacturing. Para la mejora en la producción mediante láser de femtosegundo se propone la implementación de un sistema de focalización espacio-temporal que, mediante la variación de la duración temporal de los pulsos fuera de foco, consigue suprimir los efectos no lineales en el medio líquido. Para la mejora en el proceso de reducción del tamaño de coloides, se propone un sistema de flujo continuo que aumenta el control sobre los parámetros de irradiación. Finalmente, los puntos cuánticos de carbono generados se utilizan como marcadores fluorescentes y se sintetizan distintas nanopartículas metálicas y óxidos para su posterior aplicación como bactericidas y en la mejora de materiales utilizados en fabricación aditiva.
Ferreira, Danilo Cardoso [UNESP]. "Elaboração de um material didático aplicado ao ensino de física para utilização do experimento virtual da dupla fenda." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/132892.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A mecânica quântica é uma das áreas da Física que surgiu em meados de 1900 e permanece em desenvolvimento até os dias atuais. Diversos aparatos tecnológicos são consequência deste importante ramo da Física que também contribui com a Medicina, Matemática, Filosofia, Literatura e Biologia. Logo, é imprescindível que o contato com esta ciência ocorra no contexto do ensino médio. Para inserir o estudante no mundo da mecânica quântica, isto é, na física do infinitamente pequeno, o aluno deve abandonar o pensamento clássico e pensar em termos do comportamento quântico e do indeterminismo no processo de medida, isto é, desenvolver a capacidade de abstração. Sendo este, o objetivo deste trabalho. Para tanto, foi escolhido o experimento da dupla fenda que permite trabalhar com a dualidade onda-partícula do elétron e do fóton. Por meio deste experimento, o aluno pode ser inserido paulatinamente numa trajetória rumo a descrição quântica necessária para o exame dos fenômenos subatômicos. A análise experimental é cuidadosamente realizada com o auxílio de laboratórios virtuais, disponibilizados gratuitamente em sítios eletrônicos, os quais representam um recurso que permite realizar procedimentos experimentais que necessitariam de grande aparato laboratorial. O experimento da dupla fenda é analisado em três etapas, relatadas a seguir: (i) a dupla fenda com partículas clássicas; (ii) a dupla fenda com ondas clássicas e; (iii) a dupla fenda com objetos quânticos como elétrons e fótons. O objetivo é demonstrar o comportamento dual do elétron. Posteriormente, para concluir de forma precisa e justificar o comportamento quântico do elétron é apresentado o princípio da indeterminação de Heisenberg e suas implicações filosóficas. Sendo assim, o objetivo central desta pesquisa é buscar integrar o comportamento quântico, que acontece na escala atômica, principalmente no contexto do ensino médio. Algumas orientações sobre como aplicar este trabalho em outros níveis de ensino aparecem no decorrer do texto e nos apêndices. Apresentando o comportamento dual, onda–partícula, do elétron, a interpretação probabilística e o princípio de incerteza. Acreditamos que o aluno será capaz de compreender um grande número de fenômenos que acontece em escalas que não são do domínio da mecânica clássica quando, em contato com estes temas. Este tema faz parte do conteúdo de física moderna contemporânea que vem sendo abordado em livros textos e vestibulares. Além disso, algumas das novas tecnologias utilizam a física quântica, desde microscópios eletrônicos, nanotecnologia, computação quântica, semicondutores, diodos (incluindo o LED), transistores, computadores, tablets, GPS, satélites, radares, aviões, lasers, scanners de código de barras, sistemas militares de defesa, CD e Blu-Ray players, criptografia, células fotoelétricas, sensores diversos, basicamente, tudo que é eletrônico. Um dos objetivos do trabalho é verificar quais os conhecimentos prévios o corpo discente possui, antes do contato com o conteúdo de física quântica, ou seja, o que faz parte do senso comum sobre este tema. Além disso, pretendemos verificar se o aluno consegue: i) distinguir, no final da aplicação desta pesquisa, que as leis da física em escalas atômicas são diferentes das leis da física clássica, ii) a importância da mecânica quântica na tecnologia e na sociedade.
Quantum mechanics is one of the areas of physics that emerged in mid-1900 and remains in development to the current day. Several technological devices are a result of this important branch of physics that also helps to Medicine, Mathematics, Philosophy, Literature and Biology. Therefore, it is essential that contact with this science occurs at the high school level, what actually occurs in a limited way, when it happens. To place the student in the world of quantum mechanics, that is, the infinitely small of physics, the student must leave the classical thought and think in terms of the quantum behavior and indeterminacy in the measurement process, namely to develop the capacity for abstraction. This is accurately the aim of this work. Thus, the double-slit experiment that lets you work with the wave-particle duality of the electron and the photon was chosen. Through this experiment, students can be gradually inserted on a path toward quantum description necessary for the examination of subatomic phenomena. The experimental analysis is carefully performed with the aid of virtual laboratories, available for free in electronic sites, which represent a resource to perform experimental procedures that would require large laboratory apparatus. The double slit experiment is analyzed in the following three steps, reported: (i) the slit paired with classical particles; (ii) the double slit and with classical waves; (iii) the double slit with quantum objects such as electrons and photons. The goal is to demonstrate the electron dual behavior. Later to complete accurately and justify the electron quantum behavior shows the principle of indeterminacy of Heisenberg and its philosophical implications. Thus, the main objective of this research is to seek to integrate quantum behavior, which takes place at the atomic scale, especially in the high school level. Some guidance on how to apply this work in other levels of education appear throughout the text and in the appendices. Introducing the dual behavior wave-particle, the electron, the probabilistic interpretation and the uncertainty principle. We believe that students will be able to understand a number of phenomena that occurs on scales that are not the classical mechanics of the domain when in contact with these topics. This topic is part of the contemporary modern physics content that is being addressed in texts and entrance exam books. In addition, some of the new technologies using quantum physics, from electronic microscopes, nanotechnology, quantum computing, semiconductors, diodes (including LED), transistors, computers, tablets, GPS, satellites, radar, aircraft, lasers, code scanners bars, military defense systems, CD and Blu-Ray players, encryption, photoelectric cells, various sensors, basically, everything is electronic. One of the goals of the work is to check what prior knowledge the student body has, before contact with quantum physics content, so the part of common sense on this issue. In addition, we intend to verify that the student is able to: i) distinguish, at the end of the application of this research, that the laws of physics at atomic scales are different from the laws of classical physics, ii) the importance of quantum mechanics in technology and society.
Ariyawansa, Gamini. "Semiconductor Quantum Structures for Ultraviolet-to-Infrared Multi-Band Radiation Detection." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/phy_astr_diss/17.
Повний текст джерелаFu, Kai. "Growth Dynamics of Semiconductor Nanostructures by MOCVD." Doctoral thesis, KTH, Teoretisk kemi (stängd 20110512), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11447.
Повний текст джерелаQC 20100713
Kraft, Marco. "Spectroscopic characterization of upconversion nanomaterials with systematically varied material composition and surface chemistry." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/19657.
Повний текст джерелаThis PhD thesis investigated the influence of various parameters on the spectroscopic properties of so-called upconversion nanoparticles (UCNPs). A special emphasis was dedicated to hexagonal-phase sodium yttrium tetrafluoride crystals that were codoped with trivalent Yb and either Er or Tm ions. Such UCNPs can, however, experience no breakthrough in the field of UC nanotechnology before all of their important photophysical features are understood. The first study of this PhD thesis therefore investigated, why nanocrystalline upconverters with different surface chemistries convert less absorbed to emitted photons than their microcrystalline counterparts. The results revealed that upconverting crystals apparently have to be subdivided into two parts, with one being the luminescent core and the other being a completely dark shell that is quenched by surface effects and assumes an ever increasing volumetric content for small UCNPs. The second study exemplarily investigated, if a more complex particle nanostructure that consisted of a Er doped core, surrounded by a Yb doped shell, could overcome these efficiency losses, however, it concluded that it does not. Another study explored the influence of Tm doping concentrations of Yb, Tm codoped nanocrystals on their spectroscopic properties and concluded that different Tm doping concentrations are required for a maximum upconversion luminescence in the wavelength regions above 700 nm, than for the wavelength regions below that. The last study of this PhD thesis investigated the influence of a previously reported dissolution process of UCNPs in aqueous solutions on the spectroscopic properties of exemplarily chosen Yb, Tm codoped nanocrystals. These results were then utilized to identify several upconversion emission bands that can be used as a screening parameter for the long-term stability monitoring of UCNPs.
Cozzarini, Luca. "Nanomaterials based on II-VI Semiconductors." Doctoral thesis, Università degli studi di Trieste, 2012. http://hdl.handle.net/10077/7359.
Повний текст джерелаThis thesis describes: (i) synthesis and characterization of colloidal nanocrystals of II-VI semiconductor compounds; (II) development of two novel materials using such nanocrystals as “building blocks”: (IIa) a nanocrystals/polymer composite, to be used as phosphor in LED-based lighting devices; (IIb) an inorganic, nano-structured multiphase material, showing a promising geometry as an electronic intermediate band material. Different typologies of nanocrystals (single-phase, alloyed or core-shells) were successfully synthesized using air-stable, safe reagents. Their optical properties (absorption spectrum, fluorescence wavelength and fluorescence quantum yield) were mapped as function of different parameters. Good results in engineering optical properties were achieved by: (a) changing size and/or composition in single-phase nanocrystals; (b) tuning shell composition and thickness and/or mutually diffusing one material into the other in multi-phase nanocrystals. The influence of different surface ligands on optical properties and on solubility in different media was also studied. Nanocrystal/polymer composite lenses were obtained from nanocrystals with desired fluorescence wavelength and quantum yield, mixed in an appropriate solvent with polymer pellets. The mixture was drop casted or tape casted on a solid substrate, obtaining solid, transparent lenses after solvent evaporation. A nano-structured, all-inorganic material (composed of semiconducor nanocrystals embedded into a wider bandgap semiconductor) was obtained through self-assembly and densification of colloidal core-shells nanocrystals. The realization of this composite supracrystal was achieved via a multi-step process: (i) colloidal synthesis of core-shell nanocrystals; (ii) surface ligands exchange; (iii) assembly; (iv) heat treatment. Evolution of the optical properties during heat treatment suggests that it is possible to sinter the shell material without altering the internal nano-heterostructure, if temperature and time of the treatment are controlled properly.
In questa tesi sono descritti: (I) la sintesi colloidale e la caratterizzazione di nanocristalli di semiconduttori II-VI; (II) lo sviluppo, utilizzando i suddetti nanocristalli quali “unità da costruzione”, di due materiali innovativi: (IIa) un composito nanocristalli/polimero, da usare come fosforo in dispositivi per illuminazione basati su LED; (IIb) un materiale inorganico nano-strutturato multifase, con una geometria promettente quale materiale a banda elettronica intermedia. Differenti semiconduttori II-VI sono stati sintetizzati in forma di nanocristalli (monofasici, in forma di lega o in struttura di tipo “core-shell”) usando reagenti sicuri e stabili in atmosfera. Le loro proprietà ottiche (spettro di assorbimento, lunghezza d’onda di fluorescenze e resa quantica di fluorescenza) sono state mappate in funzione di numerosi parametri. Sono stati raggiunti ottimi risultati nel controllo delle proprietà ottiche sia in nanocristalli a fase singola (modificandone le dimensioni o la composizione chimica) che in nanocristalli multifase (regolandone la composizione e lo spessore della “shell”, nonché mutualmente diffondendo un materiale nell’altro). È stata anche studiata l’influenza di differenti leganti superficiali sulle proprietà ottiche e sulla solubilità dei nanocristalli in differenti solventi. Lenti composite di nanocristalli/polimero sono state ottenute a partire da nanocristalli aventi la lunghezza d’onda e la resa quantica di fluorescenza desiderate, mescolandoli con pellet di polimero in solventi appropriati. La miscela è stata depositata su un supporto, tramite drop casting o tape casting, ottenendo lenti solide trasparenti dopo l’evaporazione del solvente. Un materiale inorganico nano strutturato (costituito da nanocristalli di semiconduttore racchiusi all’interno di un secondo materiale semiconduttore a bandgap maggiore) è stato ottenuto tramite l’autoassemblaggio e la densificazione di nanocristalli core-shell sintetizzati con procedure di chimica colloidale. La realizzazione di suddetto sovra-cristallo si è svolta in più fasi: (i) sintesi colloidale; (ii) sostituzione dei leganti superficiali; (iii) assemblaggio; (iv) trattamento termico. I risultati derivanti dallo studio dell’evoluzione delle proprietà ottiche durante il trattamento termico suggeriscono che sia possibile sinterizzare il materiale della shell senza alterare la nano-eterostruttura interna, se la temperatura e il tempo del trattamento sono scelti opportunamente.
XXIV Ciclo
1983
Hoffman, Amy Jo Gray Harry B. Hoffmann Michael R. "Photocatalytic reactions on quantum-sized semiconductor colloids : photoinitiated polymerization of vinylic monomers, formation of hydrogen peroxide and organic peroxides, oxidation of carboxylic acids, and synthesis of humic-like material /." Diss., Pasadena, Calif. : California Institute of Technology, 1993. http://resolver.caltech.edu/CaltechETD:etd-09272005-134829.
Повний текст джерелаAinsebaa, Abdelmalek. "Diodes électroluminescentes hybrides organiques inorganiques : Mécanismes aux interfaces, courant et lumière." Phd thesis, Université Paris-Diderot - Paris VII, 2010. http://tel.archives-ouvertes.fr/tel-00526529.
Повний текст джерелаPinto, Melissa Fabíola Siqueira. "Estudo químico-quântico de propriedades estruturais e eletrônicas de oligofluorenos com potenciais aplicações tecnológicas." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-14042008-104809/.
Повний текст джерелаIn this thesis, the evolution of electronic and structural properties of fluorene oligomers and two derivatives were accomplished relating to the gradual insertion of monomeric units using the quantum chemical methods semiempirical, ab initio Hartree-Fock and Density Functional Theory (DFT). For this purpose, detailed methodological analyses were performed with their monomers and dimers (fluorene, FF and TFFF). These results showed that the semiempirical methods AM1 and PM3 are inadequate to describe the atomic charges derived from electrostatic potential distributions and, hence, for the properties depending of them. In addition, the conformational analysis achieved for these three dimers showed that both stable structures found for the TFFF dimer possess the same total dipole moment, this is probably due to the influence of the fluorine atoms on the system. Moreover, with investigations regarding to the gradual increase in the oligomeric chain, it was verified that the UV spectra and the frontier orbital energies calculated for the oligomers provided the same tendency bespoken by their relative polymers from cyclic voltametry and UV measurements shown in the literature. Besides, the dihedral angles found in the oligomers indicated that their conformations are not planar. Furthermore, the total energy linear decay of the TFFF oligomers behaves approximately three times faster than that exhibited by the fluorene oligomers. In this way, the applications of the Quantum Chemistry principles and the correlation between these theoretical results and experimental data reported in the literature evidenced that using these information is feasible to estimate some properties of polymers from their oligomers by means of appropriate methods of quantum chemistry.
Diestel, André Luiz Cosenza. "Uma análise de produtos educacionais para o ensino de física quântica desenvolvidos no âmbito de um Mestrado profissional em ensino de física." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/169546.
Повний текст джерелаA significant expansion of professional master’s degree (PM) in the field of Science Education is observed, since its approval in 2001. This dissertation analyses works and educational products created in the scope of professional master’s degree in Physics Teaching, focusing the topic of Quantum Physics Teaching, developed in a federal university. The research relies on a bakhtinian analysis, treating the conclusion work (dissertation + educational product) as an utterance, according to Bakhtin’s theory. From this analysis, it is possible to emphasize a series of inconsistencies that permeate the theoretical framework, in many cases used as a way of fulfilling demands, not significantly articulated to the methodological proposal, also including references that arise only to contemplate certain groups in which the author is inserted. Finally, it is highlighted the low relevance of educational products produced, which do not meet the schools’ demands, and, in many cases, follow an opposite way if compared to researches in the area of Physics Education.
Timothy, H. Hsieh Timothy (Timothy Hwa-wei). "Topological materials and quantum entanglement." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/103228.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 83-91).
As the title implies, this thesis consists of two main topics: materials which realize topological phases of matter and applications of the concept of entanglement in understanding topological phases and their transitions. The first part will focus on a particular class of materials called topological crystalline insulators (TCI), which are bulk insulators with metallic boundary states protected by crystal mirror symmetries. The realization of TCIs in the SnTe class of materials and the anti-perovskite family will be described. The second part will focus on using entanglement notions to probe a topological phase transition, based on a single topological wavefunction. This is achieved by performing extensive partitions of the wavefunction, such as a checkerboard partition. Implementing this technique in one dimension naturally involves the use of tensor networks, which will be reviewed and then utilized.
by Timothy H. Hsieh.
Ph. D.
Rival, Olivier. "Organic materials for quantum computation." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:3674b9ce-c284-47b5-ab0d-76d094c849f0.
Повний текст джерелаKozii, Vladyslav. "Exotic superconductivity in quantum materials." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/127702.
Повний текст джерелаThesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2019
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 345-342).
The theory of superconductivity developed by Bardeen, Cooper, and Schrieffer has proven to correctly describe a wide class of metals, where the effective attraction between electrons is mediated by phonons. Despite huge success, this theory fails to explain certain types of superconductivity, which includes but not limited to topological superconductivity and superconductivity in systems with low carrier density. We study new exciting properties of these materials and discuss possible microscopic mechanisms for exotic superconductivity. In Part I of this thesis, we explore the properties of two-component superconductors with strong spin-orbit coupling. Our study is motivated by the experiments on a topological superconductor candidate material, Bi2Se3 doped with Cu, Sn, or Nb atoms. Generally, superconductivity in such systems comes in two flavors: nematic, which breaks rotational symmetry of the crystal, and time-reversal breaking chiral.
We study the relative energetics and different features specific to each of these flavors. We find that, in three dimensions, the nematic superconductors generically possess full pairing gap on the Fermi surface, thus representing a solid-state realization of a time-reversal-invariant topological superconductor. On the contrary, chiral superconductors host non-degenerate point nodes on the Fermi surface and represent the superconducting analog of topological Weyl semimetals; the low-energy excitations in these materials are itinerant Majorana fermions. In Part II, we suggest possible microscopic mechanisms for unconventional superconductivity. We show that strong fluctuations of the inversion-breaking order parameter induce instability in an odd-parity superconducting channel, suggesting a route towards topological superconductivity. Using bosonization, we generalize this result to one-dimensional systems.
We apply our findings to study superconductivity in three-dimensional Dirac materials with extremely low density of carriers. Finally, we discuss the mechanism for nematic superconductivity from density wave fluctuations in two-dimensional systems, with possible application to twisted bilayer graphene. The results presented in this thesis are mainly based on Refs. [1, 2, 3, 4, 5, 6, 7].
by Vladyslav Kozii.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Physics
Vallés, Pelarda Marta. "Different approaches to improve perovskite-based photovoltaic and optoelectronic devices." Doctoral thesis, Universitat Jaume I, 2022. http://dx.doi.org/10.6035/14104.2022.368259.
Повний текст джерелаPrograma de Doctorat en Ciències
Palacios-Berraquero, Carmen. "Quantum-confined excitons in 2-dimensional materials." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275721.
Повний текст джерелаEarnshaw, Mark Peter. "Quantum well electrorefraction materials and devices." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298387.
Повний текст джерелаBabkevich, Peter. "Quantum materials explored by neutron scattering." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:5f6ef05d-e846-47e1-b59f-864ea4fa2f3f.
Повний текст джерела