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Tannenbaum, Jared Michael. "The development of a portable instrumented indentation system." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5931.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains xiv, 127 p. : ill. Includes abstract. Includes bibliographical references (p. 61-62).
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Figueiredo, Vitor Manuel Loureiro. "Development of copper and nickel based oxide thin-films: design and fabrication of thin-film transistors." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/9296.
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Carvalho, Tânia Isabel da Silva. "Development of ion jelly thin films for electrochemical devices." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10874.
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Dissertação para obtenção do Grau de Doutor em Química SustentávelIonic liquids (ILs) are promising materials which have been used in a wide range of applications. However, their major limitation is their physical state. In order to address this challenge, a self-supported IL-based material was developed by combining gelatine with an IL, originating a quasi-solid material named Ion Jelly (IJ). This is a light flexible material, dimensionally stable, with promising properties to develop safe and highly conductive electrolytes. This thesis is focused on the characterization of IJ films based on different ILs. The conductive mechanisms of IJ materials were studied using dielectric relaxation spectroscopy (DRS) in the frequency range 10-1−106 Hz. The study was complemented by differential scanning calorimetry (DSC) and pulsed field gradient nuclear magnetic resonance (PFG NMR) spectroscopy. A glass transition was detected by DSC for all materials allowing to classify them as glass formers. From dielectric measurements, transport properties such as mobility and diffusion coefficients were extracted. Moreover, it was found that the diffusion coefficients and mobility are similar for the IL and IJ, especially for the IL EMIMDCA. Since for BMIMDCA, those properties significantly change upon hydration, the influence of water content [0.4 - 30% (w/w)] was also studied for the ILs. In particular for BMPyrDCA with 30% water, it was analyzed the reorientational polarization by the complex permittivity and electric modulus, from which three different processes were identified: a secondary relaxation with Arrhenian temperature dependence, the process that is believed to be behind the dynamic glass transition and the mobility of charge carriers. An application of the IJs was successfully explored with a chemoresistive gas sensor made up by different IJs as active layer, which is an electronic nose formed by an array of such sensors. The performance of this e-nose revealed its ability to correctly detect eight common volatile solvents.
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Alfadhili, Fadhil K. "Development of Back Contacts for CdTe Thin Films Solar Cells." University of Toledo / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1588962981116943.
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Fazio, Maria Antonietta <1989>. "Development and analyses of innovative thin films for photovoltaic applications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/9028/1/PhDThesisMAFazio.pdf.
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In solar cell current research, innovative solutions and materials are continuously requested for efficiency improvements. Si-based technology rules over 95% of the market, with silicon heterojunction (SHJ) solar cell reaching 26.7% record efficiency. Nonetheless, hydrogenated amorphous silicon (a-Si:H) layers employed in the structure still have challenges, resolvable with oxygen/nitrogen inclusion. In parallel, new technologies based on different materials still lack in the market due to stability issues or low efficiencies. However, a preliminary study of their properties creates a deeper knowledge exploitable in photovoltaic application. In this perspective, we investigated both innovative Si-based materials (nanocrystalline and amorphous silicon oxy-nitride and oxide thin films, nc-SiOxNy, a-SiOxNy and a-SiOx, respectively) and innovative materials (perovskite lanthanum-vanadium oxide LaVO3 thin films, indium gallium nitride InxGa1-xN and aluminium indium gallium nitride AlxInyGa1-x-yN layers) for solar cell concepts. Different deposition conditions have been employed to extract their influence on compositional, optical, and electrical properties.
The study on nc-SiOxNy layers by conductive atomic force microscopy (c-AFM) and surface photovoltage (SPV) has allowed to clarify O, N, and B content, and annealing treatment role on microscopic transport properties.
On a-SiOx and a-SiOxNy layers, by spectral ellipsometry, Fourier transform infrared spectroscopy, photoconductance decay and SPV, we can conclude that moderate insertions of O/N in a-Si:H lead to a decrease of optical parasitic absorption, preserving the passivation quality of the layers.
The measurements by AFM and Kelvin probe force microscopy on LaVO3 have clearly shown that it is a poor charge-transport medium, thus not suitable for photovoltaic applications.
The analysis on InGaN and AlGaInN by SPV measurements has shown how low In content, Si doping and no misfit dislocations in InGaN/GaN structure cause less recombination processes at the interface, whereas, the strain relaxation (tensile and compressive) with the formation of pinholes produces better interfaces in the AlGaInN/GaN samples.
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Law, Tak Wai. "Development of low temperature processable ceramic thin film embedded capacitors /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20LAW.
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Morales, Hector Roberto. "Development and integration of thin film zinc oxide integral resistors in SOP." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/19908.
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Rincón-Rosenbaum, Charlene. "Development of poly(3-octylthiophene) thin films for regulating osteoblast growth." Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26493.
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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: J. Carson Meredith; Committee Member: Hang Lu; Committee Member: Joseph Schork; Committee Member: William Koros; Committee Member: Yadong Wang. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Rincón-Rosenbaum, Charlene. "Development of poly(3-octylthiophene) thin films for regulating osteoblast growth." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26493.
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The overall objective of this work was to assess the suitability of poly(3-octylthiophene) (P3OT) to sustain MC3T3-E1 osteoblast attachment and growth. The central hypothesis was that specific P3OT film properties (i.e., thickness, film preparation conditions, and level of doping) are able to regulate osteoblast functions (i.e., attachment and proliferation). Discrete and combinatorial techniques were utilized to prepare and characterize thin films of P3OT, a semiconductor in its undoped state, and to study its interaction with MC3T3-E1 osteoblasts.
In this work we demonstrate that P3OT is a suitable surface to sustain MC3T3-E1 attachment and proliferation with no observed cytotoxicity. We show that P3OT has an effect on MC3T3-E1 attachment and proliferation as area, circularity, and proliferation ratio are significantly different for P3OT compared to control surfaces. We also demonstrate that P3OT doping and film preparation conditions have an effect on osteoblast attachment and proliferation but that thickness over a low and high range does not affect osteoblast functions.
This work is significant because it contributes to the growing area of conducting polymers in biomedical applications and establishes P3OT as a potential cell substrate that sustains MC3T3-E1 attachment and promotes high levels of cell proliferation.
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Wilde, Stuart. "Development of superconducting thin films for use in SRF cavity applications." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/34659.
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Superconducting thin films are a possible alternative to bulk niobium for superconducting radio frequency cavity applications. Thin film cavities have produced larger Q0 than bulk niobium at low accelerating voltages [1], are less susceptible to external magnetic fields and therefore require less magnetic shielding than bulk niobium cavities [2] and can benefit from substrates which conduct heat more effectively than bulk niobium [3]. The major drawback for current thin film cavity technology is the large Q slope which is observed above accelerating gradients of 6 7 MV/m. The mechanism for the Q slope is not yet fully understood. Theories have been suggested but are not accepted by everyone within the scientific community [2, 4, 5, 6, 7]. It is assumed that a better understanding of the physical properties of superconducting films is required before the origins of the sharp Q slope can be elucidated. This study has been conducted to better understand the physical properties of superconducting thin films deposited by the magnetron sputtering process. In particular, superconducting niobium films have been deposited by high power impulse magnetron sputtering (HiPIMS) and tested by a wide range of analytical techniques as a function of the substrate temperature and applied bias during deposition. Analytical techniques which have been used include x-ray diffraction crystallography, Rutherford backscattering spectroscopy, scanning electron microscopy, residual resistance ratio, DC magnetometry and RF surface resistance measurements. Results showed that the application of an applied bias during deposition resulted in increased energy of bombarding ions and enhanced rates of surface diffusion and defect annihilation within the microstructure of a growing niobium film. However, large numbers of random complex defects formed once the energy of bombarding ions becomes too large. The systematic approach that was described to investigate the changing morphological and DC superconducting properties of deposited films, as a function of the applied bias, allowed the identification of which process conditions produce the fewest random complex defects. The same systematic investigations could be applied to any HiPIMS deposition facility to provide similar results. An important observation during the study is that the initial substrate conditions have a large influence on the properties of a deposited niobium film. Niobium films deposited onto polycrystalline copper substrate that was pre-annealed at 700 ˚C prior to deposition displayed more stable magnetic flux pinning, larger RRR and an enhanced resistance to the onset of flux penetration, than was observed for films deposited with a wide range of process conditions onto as received copper substrate. Superconductors other than niobium have been successfully deposited by HiPIMS and tested. Niobium titanium nitride thin films displayed a superconducting transition temperature up to 16.7 K, with a normal state resistivity as small as 45±7 μΩcm. The findings suggest that similar niobium titanium nitride thin films could produce smaller RF surface resistance than bulk niobium cavities at 4.2 K.
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Jiang, Hongmin. "Development of Ceramic Thin Films for High Temperature Fiber Optic Sensors." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367937316.
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Hojo, Hajime. "Development of ferromagnetic oxide semiconductor thin films for spin electronics applications." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/136297.
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Dindault, Chloe. "Development of coevaporated hybrid perovskite thin films for solar cells applications." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX079/document.
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Les pérovskites hybrides célèbrent cette année leurs 10e anniversaire dans le domaine du photovoltaïque. En plus de la progression inégalée des rendements des cellules solaires, les pérovskites ont des propriétés optoélectroniques ajustables et peuvent être fabriquées par des procédés bas coûts, ce qui en fait de sérieuses candidates pour les cellules solaires multijunctions. Le réseau cristallin caractéristique des pérovskites hybrides offre une certaine liberté, supportant l’introduction partielle de cations et d’ions halogénures multiples. L’ajustement de la composition d’un matériau pérovskite se traduit par un ajustement de ces propriétés électroniques dont notamment sa structure de bandes. En adaptant la composition il est possible d’obtenir un matériau pérovskite avec une bande interdite de 1,7 eV qui serait parfaitement adapté pour une cellule tandem à base de Silicium cristallin. Les films minces de pérovskites peuvent être fabriqués par une grande diversité de techniques de dépôt, à partir de précurseurs ‘bon marché’ (CH3NH3I et PbI2 par exemple), par des procédés à basse température. Même si la grande majorité des films de pérovskites sont obtenus par la méthode d’enduction centrifuge, celle-ci ne permet pas l’obtention de films homogènes, sur grandes surfaces et de façon répétable. Etant donné l’enjeu industriel qui attend les pérovskites et l’intérêt croissant pour les structures tandems Silicium/Pérovskite, les méthodes sans solvant semblent plus adaptées. Déjà très largement utilisé dans l’industrie des OLEDs, le procédé de coévaporation thermique semble constituer une solution commercialement viable. Publiée pour la première fois en 2013, la synthèse par coévaporation des pérovskites est pour le moment encore étudiée par peu de groupes, car nécessitant des équipements plus coûteux. La présente thèse vise à mettre en place et développer la technique de coévaporation pour la fabrication de films de pérovskites hybrides pour des applications en cellules solaires.Afin d’évaluer la faisabilité du procédé, nous avons commencé notre travail sur un réacteur de démonstration, ce qui nous a permis d’appréhender la réponse à la sublimation des deux précurseurs. Nous avons très vite identifié le comportement du sel organique CH3NH3I comme étant problématique car difficilement contrôlable (s’évaporant sous forme de « nuage »), comme nous l’avions lu dans la littérature. En six mois d’utilisation de ce réacteur, nous avons fabriqué des films de pérovskites ayant permis d’atteindre des rendements de 9% sur des cellules solaires, malheureusement avec une faible reproductibilité (que nous expliquons en partie par le caractère aléatoire de l’évaporation du composé organique CH3NH3I). Nous nous sommes trouvés dans l’incapacité de comprendre plus en profondeur le procédé à cause d’un manque de fonctionnalités de l’équipement. Grâce à ces différents retours d’expérience nous avons pu concevoir, en étroite collaboration avec l’équipementier, un réacteur semi-industriel dédié à la fabrication de films de perovskites par coévaporation. Suite à sa mise en place, nous nous somme focalisé sur la problématique de la reproductibilité dans nos expériences en essayant de diminuer l’impact du nuage organique. Bien que les efficacités atteintes en cellules solaires pour des films coévaporés fussent moindres que pour des films déposés par la technique classique d’enduction centrifuge, nous soupçonnions néanmoins une meilleure homogénéité des films obtenus par voie sèche. Nous avons ainsi intégré à cette thèse une étude comparative voie liquide/voie sèche par le biais d’une technique de spectromicroscopie rayons X en SynchrotronHybrid perovskites celebrate this year their 10-year anniversary in the photovoltaic field. Besides the unprecedented rise in solar cells efficiencies, perovskite materials have tunable optical properties and can be manufactured at low cost, making them very promising candidates for the high efficiency, multijunction solar cells strategy. Perovskite crystal structure offers a relative degree of freedom, allowing the partial integration of multiple cations and halide ions. This chemical composition tuning translates into a bandgap tuning. Through fine chemical engineering, the 1.7 eV requirement for a c-Si-based tandem device can be achieved. Perovskite thin films can be prepared by a large variety of deposition techniques, from low cost precursors (CH3NH3I and PbI2 for instance), through low-temperature processes. While most of the reported works on perovskite thin films are based on the basic wet-process spincoating technique, this latter hardly allows large scale, homogeneous and reproducible deposition. With the future challenge of industrialization and the increasing interest for the Silicon/Perovskite tandem approach, solvent-free methods appear more suitable. Already widely implemented in the OLED industry, coevaporation stands as a viable option for perovskites’ future. Reported for the first time in 2013, coevaporated perovskites are still scarcely studied compared to wet-based techniques, requiring more expensive set ups. In the present thesis, we implemented and developed the coevaporation process to fabricate perovskite thin films for solar cells applications.Starting off on a proof-of-concept reactor to assess the feasibility of the technique, we got accustomed to the perovskite precursors behaviour and identify very early on the organic precursor to be hardly manageable, as reported in the literature. In six months, we were nonetheless able to obtain nice perovskite films leading to 9% efficient photovoltaic devices, unfortunately with a poor reproducibility that we think to be partially due to the cloud vapour behaviour of CH3NH3I. We eventually found ourselves missing some features on the equipment, preventing us from accurately get a grasp on the process. From this feedback we then designed, hand in hand with the manufacturer, a dedicated semi-industrial equipment for perovskite coevaporation. Following its implementation, we then focused on establishing the reproducibility of the method, trying to mitigate the parasitic effect of the organic compound. Even though the efficiencies in solar cells were still slightly lower for coevaporated perovskites, with respect to classical spincoated ones, we expected the material homogeneity to be in favour of the vacuum-based process. We then eventually integrated to this thesis a comparative study between wet- and dry-processed perovskite films using a Synchrotron-based X-ray spectromicroscopy technique
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Polley, Todd A. "Zone model development for combustion chemical vapor deposition of zinc oxide thin films." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19565.
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Lewis, Vernon Geoffrey. "Development and applications of an alternating gradient force magnetometer." Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262528.
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Park, Jung Hyun. "Microstructure development and evolution of sputter deposited indium thin films in cryogenics." Auburn, Ala., 2007. http://repo.lib.auburn.edu/07M%20Theses/PARK_JUNG-HYUN_51.pdf.
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Park, Jung Hyun Kim Dong Joo. "Microstructure development and evolution of sputter deposited indium thin films in cryogenics." Auburn, Ala., 2007. http://repo.lib.auburn.edu/07M%20Theses/PARK_JUNG-HYUN_51.pdf.
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Lüders, Ulrike Anne. "Development and integration of oxide spinel thin films into heterostructures for spintronics." Doctoral thesis, Universitat Autònoma de Barcelona, 2005. http://hdl.handle.net/10803/3373.
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En esta memoria se describe el crecimiento, mediante pulverización catódica rf, de capas delgadas de NiFe2O4 y CoCr2O4 sobre distintos substratos y la subsiguiente caracterización magnética y eléctrica. El objetivo es integrar dichas capas en dispositivos magnetoelectrónicos tales como uniones túnel o filtros de spin.Hemos descubierto que el crecimiento epitaxial permite estabilizar fases nuevas del óxido NiFe2O4, fases que no existen en la forma másiva, y que tienen propiedades remarcablemente distintas. Como por ejemplo: un aumento dramático de la magnetización o la posibilidad de modificar drásticamente sus propiedades de transporte, pudiéndose obtener capas aislantes -como es en forma cerámica- o conductivas. Se ha realizado un estudio sistemático de los efectos del espesor de la capa y de las condiciones de crecimiento sobre las propiedades de magnetotransporte y los mecanismos de crecimiento.
Argumentamos que el aumento de la magnetización es debido a la estabilización de una fase NiFe2O4 espinela que es parcialmente inversa, en la que los iones Ni2+ están distribuidos entre las dos posiciones disponibles (tetraédrica y octaédrica) de la estructura. En la forma masiva del material los iones Ni solo se encuentran en los sitios octaédricos. La introducción adicional de vacantes de oxígeno es probablemente la causa de la existencia de una configuración electrónica mixta Fe2+/3+ en la subred octaédrica y de la alta conductividad de las capas.
Hemos aprovechado la capacidad de obtener epitaxias de NiFe2O4 ferrimagnéticas conductoras o aislantes para integrarlas en dos distintos dispositivos magnetoelectrónicos: una unión túnel magnética y un filtro de spin.
Las capas conductoras de NiFe2O4 se han empleado como electrodos ferrimagnéticos-metálicos en uniones túnel. El otro electrodo magnético es (La,Sr)MnO3 y la barrera túnel SrTiO3. Se ha podido medir una magnetoresistencia túnel importante hasta temperaturas tan altas como 280K. Los valores de magnetoresistencia corresponden a una polarización de spin del NiFe2O4 de aproximadamente un 40%, que es prácticamente independiente de la temperatura. Estos resultados sugieren que la nueva fase conductora que hemos estabilizado es un candidato interesante como fuente de corriente polarizada en spin.
Por otra parte, el NiFe2O4 aislante se ha implementado, por primera vez, como barrera túnel en una heteroestructura de filtro de spin. El electrodo magnético es (La,Sr)MnO3 y el electrodo no magnético Au. Hemos observado una magnetoresistencia túnel que alcanza valores de hasta un 50%. A partir de estas medidas, hemos deducido detalles relevantes de la estructura electrónica de la fase parcialmente inversa de NiFe2O4.
Hemos crecido el óxido CoCr2O4 sobre distintos substratos, tales como MgO(001) y MgAl2O4(001). Hemos podido comprobar que este óxido presenta una pronunciada tendencia a un crecimiento 3D. Por esta razón, las superficies de la capa no son nunca suficientemente planas y no se pueden usar en heteroestructuras túnel.
Sin embargo hemos aprovechado esta característica para controlar el crecimiento de estas estructuras 3D y hemos conseguido la formación de objetos submicrónicos, autoorganizados con formas piramidales muy bien definidas. El estudio detallado del efecto de los parámetros de crecimiento nos ha permitido por una parte, dilucidar cuales son los mecanismos que llevan a una autoorganización tan perfecta y por otra determinar que, en las condiciones adecuadas, se pueden obtener templates totalmente faceteados con múltiples posibilidades para futuras aplicaciones.
In this thesis the growth of thin films of NiFe2O4 and CoCr2O4 by RF sputtering on different oxide substrates and the characterization of their magnetic and electric properties is reported. The aim is to integrate the films into spintronic devices namely magnetic tunnel junctions and spin filter.
It was found that the epitaxial growth of these films permits to stabilize new phases of NiFe2O4, which are not found for the bulk material and which show remarkably distinct properties. A strong enhancement of the saturation magnetization was found as well as the possibility to tune the electric behaviour of the films from insulating - like in bulk NiFe2O4 - to conducting. A systematic study of the influence of the film thickness and growth parameters on the properties of the films was carried out.
The enhancement of the saturation magnetization can be explained by a partially inversed spinel structure, where the Ni2+ ions are distributed over both available sites (octahedral and tetrahedral) of the structure, whereas in bulk NiFe2O4 the Ni2+ ions are only located on the octahedral sites of the structure. An additional introduction of oxygen vacancies causes the formation of mixed valence Fe2+/3+ chains on the octahedral sites and thus a hopping conductivity.
We have taken advantage of our ability to obtain epitaxial ferromagnetic NiFe2O4 films of insulating or conducting character to integrate them in two different spintronic devices: the magnetic tunnel junction and the spin filter.
The conducting NiFe2O4 was integrated in a magnetic tunnel junction as a magnetic electrode, with a (La,Sr)MnO3 counterelectrode and a SrTiO3 barrier. A magnetoresistance was measured up to a temperature of 280K. The values of the magnetoresistance correspond to a spin-polarization of 40%, which is basically constant in temperature. This results show that the conductive phase of NiFe2O4 is an interesting candidate for the application as a source of highly spin-polarized current.
On the other hand the insulating NiFe2O4 has been integrated into a spin filter as the magnetic barrier. The magnetic electrode was again (La,Sr)MnO3 and the counter electrode Au. A magnetoresistance up to 50% was observed. It was possible to deduce the band structure of NiFe2O4 from these measurements.
Thin films of CoCr2O4 were grown on different substrates like MgO(001) or MgAl2O4(001). It was found that the material shows a pronounced tendency to grow in a three dimensional manner. Thus the surface of these films is not sufficiently smooth to integrate them into tunnel contacts.
However, we were able to control the growth and morphology of the three dimensional structures leading to the formation of submicron self-organized pyramids with a square or elongated base. By a detailed study of the influence of the growth parameters it was possible to elucidate the underlying growth mechanisms and to obtain a fully faceted surface, which can be used in different applications.
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Luders, Ulrike. "Development and integration of oxide spinel thin films into heterostructures for spintronics." Phd thesis, INSA de Toulouse, 2005. http://tel.archives-ouvertes.fr/tel-00011342.
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Des couches minces à base de NiFe2O4 et CoCr2O4 ont été réalisées par pulvérisation cathodique sur des substrats d'oxydes, dans le but de les intégrer dans des hétérostructures pour l'électronique de spin.Il a été montré que la croissance épitaxiale permet la stabilisation de nouvelles phases de NiFe2O4 qui n'existent pas sous forme massive. Ces phases présentent une augmentation forte du moment magnétique ou la possibilité d'ajuster les propriétés électriques du matériaux. Nous expliquons l'augmentation du moment magnétique par une inversion partielle des sites cationiques du NiFe2O4, matériau dans lequel les ions Ni2+ sont répartis entre les deux sites de la structure spinelle. Les lacunes en oxygène sont susceptibles de favoriser un comportement conducteur en induisant des états de valence mixte Fe2+/3+ dans les sites octaédriques.
Des couches minces de NiFe2O4 conducteur ont été utilisées comme électrodes ferrimagnétiques dans des jonctions tunnel. Une magnétorésistance significative a été mesurée, correspondant à une polarisation de spin de 40% du NiFe2O4 pratiquement constante en température. Le NiFe2O4 isolant a été incorporé avec succès en tant que barrière tunnel ferrimagnétique au sein de jonctions de type "filtre à spin", ce qui en fait la première structure de ce type réalisée avec des oxydes complexes.
Il a été mis en évidence que les couches minces de CoCr2O4 ont une tendance forte à croître de manière tridimensionnelle de la forme des objets pyramidaux aux facettes parfaitement définies. Cette croissance auto-organisée de nano-objets et sa dépendance à l'égard des conditions de dépôt été étudie en detail.
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Speller, Susannah. "Microstructural development and control in Tl₂Ba₂CaCu₂O₈ thin films." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401148.
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Hyland, David M. C. "The development of Tl-2212 based superconducting thin films for microwave applications." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249565.
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Fairley, Kurtis. "Development and Applications of Thin Film Resists for Electron Beam Lithography." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/19703.
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Throughout this work several thin film resists have been studied with substantial focus on HafSOx and SU-8. The study of HafSOx has granted more insight into how inorganic, spin coated films form and react under the electron beam. These films have been shown to form a thin dense crust at the surface that could have interesting implications in the interaction of the electrons. Continuing to further understand the electron interactions within the resist, low voltage patterns were created allowing the accelerating voltage to be matched to the film. With this general knowledge, higher resolution films can be constructed with shorter patterning times. Both resists complement each other in that HafSOx produces incredibly thin, dense structures to be formed with features below 10 nm in all dimensions. SU-8 allows micron thick features to be created over several millimeters. This flexibility in feature size enabled the creation of large fractals that could improve neuron binding to artificial retina down to the smallest fractals reported that are interesting for their applications as antennas. The final facet of this work involved looking at other methods of making structures. This was done through adding differing salts to organic molecules that stack into unique crystals.
This dissertation includes previously published co-authored material.
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Chen, Tung-sheng. "Technology development of ferroelectric capacitors with iridium electrodes for ULSI memory applications /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Bauers, Sage. "Nanoarchitecture-property Relationships in Tise2 Based Nanolaminates for Development of Novel Design Strategies in Composite Thermoelectric Materials." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22264.
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This dissertation is centered on investigation of metastable thermoelectric thin film materials and is split into 3 primary sections. Section 1 focuses on formation mechanisms of FeSbx compounds from layered precursors. It was found that a compositionally favorable and homogeneous nucleation environment allowed for the nucleation of a metastable phase, which surprisingly resembles the local coordination environment of the precursors, even in cases where they are compositionally unfavorable. Over the course of this work, the technique of normal-incidence thin film pair distribution function analysis is introduced, which allows for rapid acquisition and analysis of local structure data from intact thin films.
Section 2 investigates changes in the stacking sequences of ([PbSe]1+δ)m(TiSe2)n nanolaminate materials, which consist of interleaved layers of each compound in the chemical formula, and how these changes effect the thermoelectric power factor. Homologous series of systematically varying m and n values are investigated and measured properties are correlated back to the designed nanoarchitecture of the laminate materials. It is found that the compounds are stabilized by electron exchange between constituents at the interfaces, and that ‘doping’ of the laminate structure by changing the relative amounts of each constituent is an effective means of optimizing their transport properties. It is also shown that interface density between constituents can be utilized to optimize performance.
Section 3 moves from the case of PbSe layers, which maintain their structure, to SnSe layers that significantly distort as the layer size is changed. The distortions in SnSe are observed to occur from templating off TiSe2 layers. As the size of the SnSe layers increases, relatively fewer templated interfacial atoms exist and stabilization of interior atoms must also be considered. The coarse behaviors developed in ([PbSe]1+δ)m(TiSe2)n hold, but the structural distortions in SnSe likely change the band structure of this constituent and hence the composite material, complicating the analysis. In some cases, these changes allow for radically different behavior, best exemplified with high TiSe2 ratios in ([SnSe]1+δ)1(TiSe2)n displaying significant enhancement of the Seebeck coefficient at cryogenic temperatures over the low-n and PbSe-containing analogues.
This dissertation includes previously published and unpublished coauthored material.
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Yavas, Hakan. "Development Of Indium Tin Oxide (ito) Nanoparticle Incorporated Transparent Conductive Oxide Thin Films." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614475/index.pdf.
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Indium tin oxide (ITO) thin films have been used as transparent electrodes in many technological applications such as display panels, solar cells, touch screens and electrochromic devices. Commercial grade ITO thin films are usually deposited by sputtering. Solution-based coating methods, such as sol-gel however, can be simple and economic alternative method for obtaining oxide films and also ITO. In this thesis, &ldquoITO sols&rdquo
and &ldquo
ITO nanoparticle-incorporated hybrid ITO coating sols&rdquo
were prepared using indium chloride (InCl3
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Nasikkar, Paresh S. "The development of cuIn1-xALSe2 thin films for use in photovoltaic solar cells." Thesis, Northumbria University, 2009. http://nrl.northumbria.ac.uk/1830/.
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The aim of the work presented in this thesis was to develop CuInSe2 (CIS) and CuIni_„Al„Se2 (CIAS) thin films for application in photovoltaic (PV) solar cells. The purpose of the addition of aluminium (Al) in CIS thin films was to modify the energy band gap of the thin films to be nearer to the optimum for PV energy conversion and to replace the less abundant element, gallium (Ga) in CuIni_,,Ga,Se2 (CIGS) solar cells. This also makes possible the production of tandem solar cells using CIAS to make the wide energy band gap top cell and the CIS to make the narrow energy band gap lower cell. The use of very thin CIS and CIAS absorber layers in solar cell structures was also investigated; the aim was to reduce the amount of indium (In) in cell production. The CIS and CIAS absorber films were prepared by a sequential two step method in which Cu-In and Cu-In-Al precursor layers were magnetron sputter deposited onto Mo-coated soda lime glass (SLG) substrates; the CIS or CIAS was then formed by heating in a selenium (Se) containing environment. Thin film solar cells were developed in the substrate configuration and had the structure Ni-Al/Indium tin oxide (ITO)/i-ZnO/CdS/CIAS/Mo/SLG. In order to achieve high efficiency solar cells it is an important to optimse the back contact molybdenum (Mo) layer, the absorber layer, the CdS buffer layer, the window layer and top contact layers. The work described in this thesis focused on the optimisation of the back contact and absorber layers. The thin films were characterised mainly using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDS), scanning electron microscopy (SEM), secondary ion mass spectroscopy (MiniSIMS), atomic force microscopy (AFM) and using spectroscopy measurements to investigate the effect of processing conditions on the composition, crystal structure, surface morphology and the optical properties of the films. The solar cells were characterised by current-voltage (/- V) and incident photon-to-photocurrent conversion efficiency (IPCE) measurements. Both Mo single and bilayer structures were investigated. It was found that single layers had better properties than Mo bilayers. The optimisation of the Mo deposition sputtering process yielded Mo layers which had good adherence and were conformal to the glass substrates, had low resistivity (29 if .cm), were pin hole free and had good crystallinity. The influence of Cu-In precursor layers with thicknesses in the range 90-400 nm on the microstructure of the CIS thin films (thicknesses in the range 400-1600 nm) was investigated. Solar cells fabricated from the CIS films of thicknesses 500 nm and 900 nm yielded highest cell conversion efficiencies of 4.3% and 8.2%, respectively. The selenisation of the magnetron sputter deposited Cu-In-Al precursor layers was carried out at a temperature of 550°C. Films were poor in surface quality and adhesion. Films prepared from the precursor layer with n [(Al/(Al+In))] = 0.21 had a non-uniform Al depth profile towards the bottom of the film. Although the film was found to be photoactive its effective energy band gap was 0.98 eV suggesting the properties of CIS. This confirmed incomplete mixing of Al in the thin films which was considered to be segregated at the bottom of the film. The thinner layers of Cu-In-Al precursors with thicknesses in the range 0.55¬1.00 gm and n [(Al/Al+In)] in the range 0.28-0.54 were magnetron sputter deposited. The precursor layers showed the prominent binary A1Cu4 compound with a uniform distribution of Al in the layer. Thin films converted from these precursor layers of thicknesses in the range 1.3-2.0 pm were fairly uniform in surface structure. Films with x 0.2 were found to have an energy bandgap of 1.10 eV and were also photoactive. Solar cells fabricated from this absorber film yielded a highest cell efficiency of 4.9%. Environmental impact assessments have been made on materials and the processes used in the fabrication of CIS and CIAS.
27
Sumner, Claire. "Development of a biosensor based on enzyme-catalysed degradation of thin polymer films." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341818.
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Joyce, Donna Marie. "The Development of DNA-Based Bio-Polymer Hybrid Thin Films for Capacitor Applications." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1389285491.
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Rastjoo, Sanaz [Verfasser], and M. [Akademischer Betreuer] Kohl. "Development of Nanodevices Based on VO₂ Thin Films / Sanaz Rastjoo ; Betreuer: M. Kohl." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1213351812/34.
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Habis, Christelle. "Development of ZnO-FTO nanocomposites for the use in transparent conductive thin films." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0192.
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Cette thèse s'inscrit dans le cadre de développement de couches d'oxyde transparentes avec des techniques à faible cout, basées sur des matériaux non polluants permettant de fonctionnaliser des dispositifs opérationnels efficace, donc à haut rendement pour la production d'énergies renouvelables. Notre choix s'est porté plus particulièrement sur l'étude des couches TCO à base d'étain et dopés au fluor, F :SnO2, dénommées FTO pour « Fluor Tin Oxydes ». Les FTO sont des oxydes à large bande interdite, à l'instar du ZnO, TiO2, Al2O3, purs ou dopés. Ces couches possèdent en principe un facteur de diffusion, défini précédemment, élevé afin d'améliorer le chemin optique et l'absorption. De plus, la texture optique des TCO peut être facilement contrôlée par dépôt de suspensions de nanostructures avant le dépôt de la couche. Généralement, ces nanostructures sont des nanoparticules voire nano-fils de carbone ou nano-fils métalliques (argent, cuivre, …) et plus récemment des nano-fils de TiO2 (présentant l'inconvénient de l'élément titane) ou de ZnO non-dopés qui diminuent, malheureusement la conductivité du fait de l'augmentation de la résistance d'interface avec la concentration des nanoparticules. C'est pourquoi, nous proposons l'étude de couches de FTO, pures et également en présence de nanofibres de ZnO et ZnO:Al par électrofilage à partir d'une solution à base de PVA afin d'avoir une couche nanostructuré ayant des propriétés de transparence et de conductivité électrique améliorées pour être intégrer comme électrodes transparentes dans les cellules photovoltaïques, répondant aux critères performatifs définis ci-dessus. Les croissances des couches seront suivies par des études morphologiques et structurales, en utilisant des techniques de caractérisations disponibles au sein du laboratoire LMOPS et de l'Université de Lorraine ( tel que: MEB, Raman, EDX, DRX, spectroscopie UV-vis, ATG, AFM, profilomètre). Enfin, les propriétés électriques et optiques, en particulier l'absorption et le facteur de Haze, seront aussi largement investies sur les couches sélectionnées présentant les meilleures propriétés structurales et morphologiqueMy thesis work entitled “Development of ZnO-FTO nanocomposites for the use in transparent conductive thin films” is supervised by Professor Michel Aillerie at University of Lorraine. This work was mainly made at the “Laboratoire des Matériaux Optiques, Photoniques et Systèmes” LMOPS in Centrale Supélec, Metz. Although this work forms a whole in the elaboration of transparent conductive oxides, it is divided into two parts. The first part consists on identifying the properties of bulk materials (ZnO and FTO) deposited in the form of thin film. Whereas, the second part is about the elaboration and characterization of Zinc Oxide (ZnO) and Aluminum doped Zinc Oxide (AZO) nanofibers, then associated to FTO thin films to form nanocomposite. The main objective of this work is to make flexible electrodes using low cost and abundant material, but also improving the optical properties and more specifically the haze factor of the nanocomposite layers.Transparent conductive oxides (TCOs) are technologically significant class of materials extensively used in thin film solar cells due to their ability to transmit light and collect charge carriers. In addition to the fundamental qualities of transparency and conductivity, the TCOs are frequently desired to have a certain degree of surface roughness (i.e., texture) in order to effectively scatter transmitted light into the active materials, therefore lengthen the optical path and, as a result, enhance the performance of the cell and light absorption. This thesis focuses on the development of low-cost fabrication techniques for transparent oxide layers using non-polluting materials to enable the functionalization of operational devices with high efficiency for renewable energy production. The choice was made to study tin-based TCO layers doped with fluorine, F:SnO2, known as FTOs for "Fluor Tin Oxides". FTOs are wide band gap oxides, like ZnO, TiO2, Al2O3, pure or doped. In principle, these layers have a high scattering factor, as defined above, in order to improve the optical path and absorption. In addition, the optical texture of TCOs can be easily controlled by depositing suspensions of nanostructures before the film deposition. Generally, these nanostructures are nanoparticles or even carbon nanowires or metallic nanowires (silver, copper, ...) and more recently nanowires of TiO2 (presenting the disadvantage of the titanium element) or of undoped ZnO which unfortunately decrease the conductivity due to the increase of the interface resistance with the concentration of the nanoparticles.Therefore, we propose the study of FTO thin films, pure and also in the presence of ZnO and AZO nanofibers by electrospinning from a PVA-based solution in order to have a nanostructured layer with improved transparency and electrical conductivity properties to be integrated as transparent electrodes in photovoltaic cells, meeting the performance criteria defined above. With the characterization techniques available in the LMOPS laboratory and the University of Lorraine (SEM, Raman, EDX, DRX, UV-vis Spectro, ATG, AFM, profilometer) the growth will be followed by morphological and structural studies of the layers. Finally, electrical and optical properties, in particular absorption and scattering factor, will also be extensively investigated on selected layers with the best structural and morphological properties and the minimum of interface defects when deposited on a PV structure
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Stewart, Brian K. "Development of a Thin-Film Evaporative Cooling System for a High Energy Thulium Holmium: Lutetium Lithium Flouride Solid-State Laser Oscillator Crystal." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/6973.
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The feasibility and critical design parameters for the development of a thin-film evaporative cooling concept for a high energy, pulsed solid-state laser oscillator were investigated. The scope of the investigation was broad, and a multidisciplinary approach was employed. No contra-indicators for the feasibility of the proposed system were revealed.
A 1-dimensional two-fluid was developed to model the hydrodynamic flow and heat transfer assuming a constant wall heat flux. This analysis produced nominal pressure drops for the flow required, indicating nominal power will be required to transport fluid across the crystal surface.
Interfacial experiments reveal that the laser crystal material has a surface energy of approximately 30 mN/m, and is highly dispersive in nature.
Design rules to allow for the orthotropic thermal expansion of the crystal rod surrounded by a thin metal sleeve were developed to support the design of a hermetic crystal-metal seal. The results indicate that commercially pure nickel produces minimal joint stresses for large thermal excursions.
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Morris, George William. "Superconductive thin films and devices : some developments and applications." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235977.
Full textAbstract:
This thesis begins by overviewing 'The Theoretical Base' of superconductivity and tunnelling. The development is attempted of a model by means of which the principles entering into the design of devices, and their resultant characteristics, can be understood. No attempt is made to present a full review of theory (ie aspects not relevant to some later practical point are omitted or are dealt with very briefly), and no new theoretical contributions of my own are presented. It is the objective of the first of three practical chapters, 'The Superconductive Tunnel Junction', to show how practical devices (in particular thin film tunnel junctions) can be produced whose current/voltage (IV) characteristics well approximate those obtained theoretically. After briefly reviewing superconductive devices in general the 'whole-wafer' technique of junction fabrication, now the basis of essentially all device fabrication within the group of which I am a part, is introduced and discussed. Practical thin film deposition and device fabrication are then detailed, after which the saga of the development of working junctions and reliable fabrication routes (which formed a major part of my own work) is related. IV characteristics typical of the reliable high quality devices now routinely available are reported. Finally some further results (stemming from the work of the group as a whole), expanding our understanding of the influences of wafer deposition conditions on device characteristics and quality, are presented, together with a discussion of some early special devices (series junctions and shunted junctions) that seem to be leading on to useful applications as development proceeds. It has long been known that superconductors can be used as the active elements in particle detectors. In collaboration with Dr Norman Booth and his colleagues at the Department of Nuclear Physics of the University of Oxford, 'first base' experiments to investigate, on a small scale, techniques of device fabrication that might be required in constructing large scale bulk detectors have been carried out; devices being fabricated by myself and tested collaboratively with the Oxford group. The initial stimulus for this work was the problem of the 'missing' solar neutrinos, which Booth and others believe might best be addressed via a superior experimental measurement performed using a solid state detector based on bulk indium. It is now believed that the general conclusions of the work and the techniques evolved in their finding ought to have general applicability to the high energy-resolution detection of a variety of forms of radiation, such as X- and gamma rays. Objectives were perceived to be the designing and building of reproducible, robust, high quality junctions, incorporating a 'quasiparticle trap' (a novel technique of signal concentration); the production of equivalent junctions in contact with a bulk single crystal of indium; and the investigation of the feasibility of detecting, via such a junction, a signal injected at a point in the bulk crystal. Chapter three, 'Devices for Particle Detection and The Quasiparticle Trap', explores the background to, and development of, work towards the attainment of these objectives, and, before going on to point out difficulties and suggest possible directions for future development, presents and discusses results obtained. One of the original objectives of my work was that once - or if - reliable routes to niobium based devices had been achieved, an attempt should be made to extend deposition and fabrication technologies to high critical temperature materials. Of course at the time this objective was established such materials as niobium germanium (Nb3Ge) and niobium nitride (NbN) were the ones in mind: alloys of the existing elemental superconductors. Work in this area had just begun (first films of niobium germanium having been made, using a composite target) when the news of the discovery by Bednorz and Muller of what turned out to be the first of a family (or family of families) of wholly new oxide superconductors, and all its consequences, burst upon the scene. Having had many years of experience with superconductive devices and also with the deposition of films of a variety of materials the group of which I am a part was well placed to attempt to produce films and devices using the new oxides. Chapter four begins with an outline of the Nobel prize winning work and discoveries of Bednorz and Muller, after which theoretical ideas that have emerged, and are emerging, to explain the behaviour of these materials, are very briefly outlined and discussed. The saga of the development of the first superconducting Y-Ba-Cu-O films is then related, in a semi-chronological manner; although, to avoid excessive un-clarity (...very much 'the way it was'(Missing data....) many facets of the deposition are discussed in the light of information only later becoming available. After this possible future courses for film development are outlined, most of which have been investigated to a certain extent, and their promise and problems discussed. A number of rudimentary device structures have been created using YBCO films, and the techniques of their fabrication, together with interpretations of the observed characteristics, are outlined. Finally future devices and applications are considered.
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Shioya, Nobutaka. "Development of Analytical Technique of Molecular Orientation in a Thin Film and Its Application to Low-Crystallinity Organic Thin Films Having a Surface Roughness." Kyoto University, 2018. http://hdl.handle.net/2433/232268.
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Richards, Mark Rowse. "Process development for IrAl coated SiC-C functionally graded material for the oxidation protection of graphite /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/10574.
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Simsek, Yusuf. "Development Of Software For Calculations Of The Reflectance, Transmittance And Absorptance Of Multilayered Thin Films." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610275/index.pdf.
Full textAbstract:
The aim of this study is to develop a software which calculates reflection, transmission
and absorption of multilayered thin films by using complex indices of refraction, as
a function of both wavelength and thickness. For these calculations matrix methods
will be considered and this software is programmed with the matrix method. Outputs
of the program will be compared with the theoretical and experimental results studied
in the scientific papers.
36
BAYONA, GUSTAVO ADOLFO LANZA. "DEVELOPMENT OF ITO THIN FILMS FOR INVERTED (IOLEDS) AND TRANSPARENT (TOLEDS) ORGANIC ELECTROLUMINESCENT DEVICES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=21772@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
Neste trabalho são apresentados os resultados da produção e caracterização de dispositivos orgânicos emissores de luz invertidos (IOLEDs) e trasnparentes (TOLEDs). Como eletrodo superior transparente , utilizou-se o óxido de índio estranho (ITO), que foi depositado via pulverização catadótica assistida por radiofrequência sobre camadas protetoras ôrganicas (CuPC) e metálicas (Alumínio). Para evitar possivéis danos efetuados nas camadas dos dispositivos pelo processo de pulverização catódica, as disposições de ITO foram realizadas a baixa potência. Primeiramente, os filmes de ITO foram caracterizados elétrica e opticamente. A seguir, foi estudada a interaçãoentre a superfície das camadas protetoras (CuPC e Alumínio) e o filme de ITO. Por fim, os dispositivos IOLEDs e TOLEDs foram caracterizados através de medidas de eletromuninescência, densidade de corrente e luminância, todas elas, em função da tensão aplicada. A paritir desses estudos foi possivélproduzir dipositivos de TOLEDscom transmitânciamédia de 70 por cento na região do espectro visível.
This work presents the results of production and characterization of organic light emitting devices inverted (IOLEDs) and transparent (TOLEDs). As transparent top electrode, a thin film of indium tin oxide (ITO) deposited via rf magnetron sputtering was used. The ITO films were deposited onto organic (CuPC) and metal (Aluminum) protective layers. In order to provent the damage incurred on the organic and metal layers by the sputtering process, the ITO disposition carried out at room temperature and under low rf power. First, the ITO films were characterized by electrical and optical measures. Next, the interaction between the surface of the protective layers (CuPC and Aluminum) and the ITO film was analyzed. Finally, the IOLEDs and TOLEDs devices were characterized by electroluminescence, current density and luminance measures, all as a function of the applied voltage. Form the studies, was possible to produce IOLEDs devicesonto opaque substrates and TOLEDs devices whit average transmittance of 70 per cent in the visible range.
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Banfield, Sarah. "Development and evaluation of aluminium-based thin films as potential alternatives to cadmium coatings." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/21319/.
Full textAbstract:
Electroplated cadmium coatings have been extensively used for many years in the military, marine and aerospace industries to provide corrosion protection to steel substrates. Cadmium coatings act as a barrier layer, protecting the substrate from corrosion attack. They continue to offer protection even when damaged. Cadmium deposits also offer sacrificial protection by preferentially corroding and galvanic protection to coated components in contact with other metals such as aluminium. However the hazardous nature of cadmium which is harmful to both humans and the environment, is a major issue. Started over 30 years ago, research into finding more environmentally-friendly alternatives continues as no substitute coating has yet been developed which could replace cadmium over the full range of applications. In this study, metallic AlCr(N) coatings containing 4 – 16 at% Cr and two different nitrogen contents (11-12 at% and 18 at%), were deposited by magnetron sputtering on stainless steel substrates - following initial coating deposition trials by both magnetron sputtering and electron-beam PVD. The coatings were then analysed to evaluate their mechanical, tribological and structural properties before being corrosion-tested using a novel AC/DC/AC cyclic test equipped with a pH monitoring system. The results indicate significant improvement in the mechanical (hardness range: 2 – 3.9 GPa) and tribological properties of the coatings with increasing alloying element content. In terms of corrosion performance, AlCr(N) with the lowest Cr content (i.e. 4 at%) displayed the best corrosion resistance properties owing to the formation of a thick and stable passive film within the pores as well as on the coating surface, providing excellent barrier corrosion protection. These promising results could be used to design graded Al-rich coatings in which individual layers are tailored to meet specific property requirements depending on the intended application, thereby enabling the replacement of cadmium on a range of steels and other engineering materials.
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Loizillon, Jérôme. "Development of ellipsometry porosimetry for the characterization of nanoporous thin films applied to photovoltaics." Electronic Thesis or Diss., Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0308.
Full textAbstract:
Avec le développement des nanotechnologies, la nécessité d’élaborer des matériaux à très petite échelle s’est accrue. En particulier, les couches minces (du nanomètre au micromètre) nanoporeuses sont utilisées dans de nombreux domaines tels que l’optique, l’électronique, ou la détection. Leur utilisation principale en tant que revêtement anti-reflets est cruciale pour les panneaux solaires en permettant d’augmenter leur rendement global. Pour ce type d’application, les couches minces doivent être en mesure de supporter des phénomènes d’abrasion (sable, nettoyage) ou des attaques chimiques (pluie, pollution). La caractérisation de la porosité des couches minces est un prérequis pour ajuster leurs propriétés mais également suivre l’évolution de la couche lors de son vieillissement. L’ellipsométrie porosimétrie, technique basée sur la sorption de gaz dans la porosité, est un des outils les plus adaptées pour cette tâche. Dans cette thèse, de nouveaux revêtements anti-reflets pour panneaux solaires ont été élaborés et leur résistance à leur environnement éprouvée. La caractérisation de leur porosité a été améliorée grâce au développement de l’ellipsométrie porosimétrie au-delà de l’état de l’art actuel. La précision de celle-ci a été évaluée par comparaison avec une autre technique. De plus, une meilleure caractérisation des interconnexions entre les pores a pu être atteinte en ajoutant une nouvelle méthode d’analyse. Cela a également permis d’établir une meilleure compréhension fondamentale des phénomènes d’adsorption dans les couches minces nanoporeusesWith the development of nanotechnologies, the elaboration of materials at a very small scale has grown as an increasing necessity. In particular, nanoporous thin films (from nanometer to micrometer) are found in many different domains such as optics, electronics, protection or sensing. Their main use as antireflective coatings is of particular interest for photovoltaics, increasing their global yield. In such applications, thin films must be designed to survive various conditions, such as abrasion (sand blasting, cleaning) or chemical attacks (rain and pollution). The characterization of the nanoporosity of thin films is a prerequisite not only to adjust the properties, but also to follow the evolution of the porous structure upon aging in operating conditions. Ellipsometry porosimetry, a technique relying on the sorption of a gas inside the porosity, is one of the best candidates for this purpose. In this thesis, new antireflective coatings for photovoltaic top glass covers were elaborated and their resistance to their environment was tested. Their characterization, which can be extended to any nanoporous thin film, was improved by developing ellipsometry porosimetry above the current state of the art. The precision of the technique was assessed by comparing it with an independent method, and a better characterization of the pore interconnections was achieved by implementing an additional mode of analysis. By doing so, a better fundamental understanding of the sorption mechanisms in nanoporous thin films was established
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Seo, Sang-Woo. "Development of thin film photodetectors and their applications multispectral detection and high speed optical interconnections /." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180408/unrestricted/seo%5fsang-woo%5f200312%5fphd.pdf.
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Brevnov, Dmitri A. "Development and application electrochemical and spectrophotometric methods based upon AC potential modulation for characterization of hybrid bilayer membranes and electroactive self-assembled monolayers supported on gold electrodes." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1462.
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Kobayashi, Takahiro. "Development and application of the DGT technique for the measurement of nitrate, ammonia and phosphate in natural waters, sediments and soils." Thesis, Lancaster University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302435.
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Knowles, Michelle Kay. "Fourier Imaging Correlation Spectroscopy : technique development and application to colloidal thin films and intracellular mitochondrial transport /." view abstract or download file of text, 2003. http://wwwlib.umi.com/cr/uoregon/fullcit?p3113013.
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Thesis (Ph. D.)--University of Oregon, 2003.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 205-212). Also available for download via the World Wide Web; free to University of Oregon users.
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Bansal, Lalitkumar El-Sherif Mahmoud Abd-El-Rahman. "Development of a fiber optic chemical sensor for detection of toxic vapors /." Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/372.
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Jiang, Dianlu, and n/a. "Studies of Photocatalytic Processes at Nanoporous TiO2 Film Electrodes by Photoelectrochemical Techniques and Development of a Novel Methodology for Rapid Determination of Chemical Oxygen Demand." Griffith University. School of Environmental and Applied Science, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040723.155003.
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In this work, a series of simple, rapid and effective photoelectrochemical methodologies have been developed and successfully applied to the study of kinetic and thermodynamic characteristics of photocatalytic oxidation processes at TiO2 nanoparticulate films. As an application of the systematic studies of photocatalytic processes by photoelectrochemical techniques, a rapid, direct, absolute, environmental-friendly and accurate COD analysis method was successfully developed. In this work, the TiO2 nanoparticles colloid was prepared by the sol-gel method. The TiO2 nanoparticles were immobilized onto ITO conducting glass slides by dip-coating method. Thermal treatment was carried out to obtain nanoporous TiO2 films of different structures. At low calcination temperature (below 600°C), nanoporous TiO2 films of pure anatase phase were prepared. At high calcination temperature (above 600°C), nanoporous TiO2 films of mixed anatase and rutile phases were obtained. At these film electrodes, the work was carried out. By employing steady state photocurrent method and choosing phthalic acid as the model compound, the photocatalytic activity of the TiO2 nanoporous films calcined at various temperatures and for different lengths of time was evaluated. It was found that the films with mixed anatase and rutile phases calcined at high temperature exhibited high photocatalytic activity. Based on semiconductor band theory, a model was proposed, which explained well this finding. By employing linear sweep voltammetry (under illumination) and choosing glucose (an effective photohole scavenger) as a model compound, the characteristics of the photocatalytic processes at nanoparticulate semiconductor electrodes were investigated. Characteristics of the nanoporous semiconductor electrodes markedly different from bulk semiconductor electrodes were observed. That is, within a large range of electrode potentials above the flat band potential the electrodes behaved as a pure resistance instead of exhibiting variable resistance expected for bulk semiconductor electrodes. The magnitude of the resistance was dependent on the properties of the electrodes and the maximum photocatalytic oxidation rate at TiO2 surface determined by the light intensity and substrate concentration. A model was proposed, which explained well the special characteristics of particulate semiconductor electrodes (nanoporous semiconductor electrodes). This is the first clear description of the overall photocatalytic process at nanoparticulate semiconductor electrodes. The investigation set a theoretical foundation for employing photoelectrochemical techniques to study photocatalytic processes. By using the transient technique (illumination step method analogous to potential step method in conventional electrochemistry), the adsorption of a number of strong adsorbates on both low temperature and high temperature calcined TiO2 nanoporous films was investigated. Similar adsorption characteristics for different adsorbates on different films were observed. In all the cases, three different surface bound complexes were identified, which was attributed to the heterogeneity of TiO2 surface. The photocatalytic degradation kinetics of the pre-adsorbed organic compounds of different chemical nature was also studied by processing the photocurrent-time profiles. Two different photocatalytic processes, exhibiting different rate characteristics, were observed. This was, again, attributed to the heterogeneity of the TiO2 surface corresponding to heterogeneous adsorption characteristics. The catalytic first order rate constants of both fast and slow processes were obtained for different organic compounds. It was found that for different adsorbates of different chemical nature the magnitudes of rate constant for the slow kinetic process were very similar, while the magnitudes of rate constant for the fast process were significantly affected by the photohole demand characteristics of different adsorbates. Photohole demand distribution that depends on the size and structure of the adsorbed molecules was believed to be responsible for the difference. By employing steady state photocurrent method, the photocatalytic degradation kinetic characteristics of both strong adsorbates and weak adsorbates of different chemical structures were compared at pure anatase TiO2 nanoporous TiO2 films as well as at anatase/rutile mixed phase TiO2 nanoporous film electrodes. At the former electrodes for all the different organic compounds studied, the photocatalytic reaction rate increased linearly with concentration at low concentrations. Under such conditions, it was demonstrated that the overall photocatalytic process was controlled by diffusion and was independent of the chemical nature of organic compounds. However, the linear concentration range and the maximum photocatalytic reaction rate at high concentrations were significantly dependent on the chemical nature of the substrates. This was explained by the difference in the interaction of different organic compounds with TiO2 surface, the difference in their photohole demand distributions at the TiO2 surface and the difference in their nature of intermediates formed during their photocatalytic mineralization. In contrast, at the latter electrodes for the photocatalytic oxidation of different organic compounds the linear ranges (diffusion control concentration range) and the maximum reaction rates at high concentration were much larger than at the former electrodes and much less dependent on the chemical nature of the organic compounds. The spatial separation of photoelectrons and photoholes (due to the coexistence of rutile phase and anatase phase) and the increase in the lifetime of photoelectrons and photoholes are responsible for the excellent photocatalytic activity of the electrodes. By employing the thin-layer photoelectrochemical technique (analogous to the thin-layer exhaustive electrolytic technique), the photocatalytic oxidation of different organic compounds at the mixed phase TiO2 nanoporous electrodes were investigated in a thin layer photoelectrochemical cell. It was found that the charge derived from exhaustive oxidation agreed well with theoretical charge expected for the mineralisation of a specific organic compound. This finding was true for all the compounds investigated and was also true for mixtures of different organic compounds. The photocatalytic degradation kinetics of different organic compounds of different chemical identities in the thin layer cell was also investigated by the photoelectrochemical method. Two kinetic processes of different decay time constants were identified, which were attributed to the degradation of preadsorbed compounds and the degradation of compounds in solution. For the degradation of compounds in solution, a change in the overall control step from substrate diffusion to heterogeneous surface reaction was observed. For different organic compounds, the variation of the rate constant was determined by the photohole demand rather than by the chemical identities of substrates. The kinetics of the fast kinetic process, on the other hand, was greatly affected by the adsorption properties of the substrates. For the strong adsorbates, the rate was much larger than for weak adsorbates. However, the rate constant of the process was independent of the chemical identities of the substrates and the variation of the constant was also determined by the photohole demand. Based on the principles of exhaustive photoelectrocatalytic degradation of organic matter in a thin layer cell, a novel, rapid, direct, environmental-friendly and absolute COD analysis method was developed. The method was tested on synthetic samples as well as real wastewater samples from a variety of industries. For synthetic samples with given compositions the COD values measured by my method agree very well with theoretical COD value. For real samples and synthetic samples the COD values measured by my method correlated very well with those measured by standard dichromate COD analysis method.
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Jiang, Dianlu. "Studies of Photocatalytic Processes at Nanoporous TiO2 Film Electrodes by Photoelectrochemical Techniques and Development of a Novel Methodology for Rapid Determination of Chemical Oxygen Dphotocatalemand." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/366458.
Full textAbstract:
In this work, a series of simple, rapid and effective photoelectrochemical methodologies have been developed and successfully applied to the study of kinetic and thermodynamic characteristics of photocatalytic oxidation processes at TiO2 nanoparticulate films. As an application of the systematic studies of photocatalytic processes by photoelectrochemical techniques, a rapid, direct, absolute, environmental-friendly and accurate COD analysis method was successfully developed. In this work, the TiO2 nanoparticles colloid was prepared by the sol-gel method. The TiO2 nanoparticles were immobilized onto ITO conducting glass slides by dip-coating method. Thermal treatment was carried out to obtain nanoporous TiO2 films of different structures. At low calcination temperature (below 600°C), nanoporous TiO2 films of pure anatase phase were prepared. At high calcination temperature (above 600°C), nanoporous TiO2 films of mixed anatase and rutile phases were obtained. At these film electrodes, the work was carried out. By employing steady state photocurrent method and choosing phthalic acid as the model compound, the photocatalytic activity of the TiO2 nanoporous films calcined at various temperatures and for different lengths of time was evaluated. It was found that the films with mixed anatase and rutile phases calcined at high temperature exhibited high photocatalytic activity. Based on semiconductor band theory, a model was proposed, which explained well this finding.
By employing linear sweep voltammetry (under illumination) and choosing glucose (an effective photohole scavenger) as a model compound, the characteristics of the photocatalytic processes at nanoparticulate semiconductor electrodes were investigated. Characteristics of the nanoporous semiconductor electrodes markedly different from bulk semiconductor electrodes were observed. That is, within a large range of electrode potentials above the flat band potential the electrodes behaved as a pure resistance instead of exhibiting variable resistance expected for bulk semiconductor electrodes. The magnitude of the resistance was dependent on the properties of the electrodes and the maximum photocatalytic oxidation rate at TiO2 surface determined by the light intensity and substrate concentration. A model was proposed, which explained well the special characteristics of particulate semiconductor electrodes (nanoporous semiconductor electrodes). This is the first clear description of the overall photocatalytic process at nanoparticulate semiconductor electrodes. The investigation set a theoretical foundation for employing photoelectrochemical techniques to study photocatalytic processes.
By using the transient technique (illumination step method analogous to potential step method in conventional electrochemistry), the adsorption of a number of strong adsorbates on both low temperature and high temperature calcined TiO2 nanoporous films was investigated. Similar adsorption characteristics for different adsorbates on different films were observed. In all the cases, three different surface bound complexes were identified, which was attributed to the heterogeneity of TiO2 surface. The photocatalytic degradation kinetics of the pre-adsorbed organic compounds of different chemical nature was also studied by processing the photocurrent-time profiles. Two different photocatalytic processes, exhibiting different rate characteristics, were observed. This was, again, attributed to the heterogeneity of the TiO2 surface corresponding to heterogeneous adsorption characteristics. The catalytic first order rate constants of both fast and slow processes were obtained for different organic compounds. It was found that for different adsorbates of different chemical nature the magnitudes of rate constant for the slow kinetic process were very similar, while the magnitudes of rate constant for the fast process were significantly affected by the photohole demand characteristics of different adsorbates. Photohole demand distribution that depends on the size and structure of the adsorbed molecules was believed to be responsible for the difference.
By employing steady state photocurrent method, the photocatalytic degradation kinetic characteristics of both strong adsorbates and weak adsorbates of different chemical structures were compared at pure anatase TiO2 nanoporous TiO2 films as well as at anatase/rutile mixed phase TiO2 nanoporous film electrodes. At the former electrodes for all the different organic compounds studied, the photocatalytic reaction rate increased linearly with concentration at low concentrations. Under such conditions, it was demonstrated that the overall photocatalytic process was controlled by diffusion and was independent of the chemical nature of organic compounds. However, the linear concentration range and the maximum photocatalytic reaction rate at high concentrations were significantly dependent on the chemical nature of the substrates. This was explained by the difference in the interaction of different organic compounds with TiO2 surface, the difference in their photohole demand distributions at the TiO2 surface and the difference in their nature of intermediates formed during their photocatalytic mineralization. In contrast, at the latter electrodes for the photocatalytic oxidation of different organic compounds the linear ranges (diffusion control concentration range) and the maximum reaction rates at high concentration were much larger than at the former electrodes and much less dependent on the chemical nature of the organic compounds. The spatial separation of photoelectrons and photoholes (due to the coexistence of rutile phase and anatase phase) and the increase in the lifetime of photoelectrons and photoholes are responsible for the excellent photocatalytic activity of the electrodes. By employing the thin-layer photoelectrochemical technique (analogous to the thin-layer exhaustive electrolytic technique), the photocatalytic oxidation of different organic compounds at the mixed phase TiO2 nanoporous electrodes were investigated in a thin layer photoelectrochemical cell. It was found that the charge derived from exhaustive oxidation agreed well with theoretical charge expected for the mineralisation of a specific organic compound. This finding was true for all the compounds investigated and was also true for mixtures of different organic compounds. The photocatalytic degradation kinetics of different organic compounds of different chemical identities in the thin layer cell was also investigated by the photoelectrochemical method. Two kinetic processes of different decay time constants were identified, which were attributed to the degradation of preadsorbed compounds and the degradation of compounds in solution. For the degradation of compounds in solution, a change in the overall control step from substrate diffusion to heterogeneous surface reaction was observed. For different organic compounds, the variation of the rate constant was determined by the photohole demand rather than by the chemical identities of substrates. The kinetics of the fast kinetic process, on the other hand, was greatly affected by the adsorption properties of the substrates. For the strong adsorbates, the rate was much larger than for weak adsorbates. However, the rate constant of the process was independent of the chemical identities of the substrates and the variation of the constant was also determined by the photohole demand.
Based on the principles of exhaustive photoelectrocatalytic degradation of organic matter in a thin layer cell, a novel, rapid, direct, environmental-friendly and absolute COD analysis method was developed. The method was tested on synthetic samples as well as real wastewater samples from a variety of industries. For synthetic samples with given compositions the COD values measured by my method agree very well with theoretical COD value. For real samples and synthetic samples the COD values measured by my method correlated very well with those measured by standard dichromate COD analysis method.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental and Applied Science
Full Text
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Gül, Semra Okur Salih. "Development of nanopatterns on self assembled monolayer (sam) organic films using scanning probe microscope (spm) nanolithography techique/." [s.l.]: [s.n.], 2006. http://library.iyte.edu.tr/tezler/master/malzemebilimivemuh/T000541.pdf.
Full textAbstract:
Thesis (Master)--İzmir Institute Of Technology, İzmir, 2006Keywords: Atomic force microscope, self assembled monolayer organic films, nanolithografy Includes bibliographical references (leaves. 109-112).
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Nistor, Iulian. "Development of magnetic field sensors using Bismuth-substituted garnets thin films with in-plane magnetization." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3436.
Full textAbstract:
Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Gkotsis, Petros. "Development of mechanical reliability testing techniques with application to thin films and piezo MEMS components." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4570.
Full textAbstract:
This work focuses on the development of a method for probing the mechani- cal response of thin film materials based on miniature tensile testing. A number of mechanisms that may compromise the performance and potentially limit the operational lifetime of MEMS devices which incorporate functional ferroelectric ceramics were also identified and investigated. Reliability of piezo MEMS com- ponents was studied at a wafer and at a device level through the development of appropriate techniques based on miniature tensile testing, time- resolved mi- cro RAMAN spectroscopy and laser Doppler vibrometry. Micro tensile testing was further used for the extraction of the elastic properties of various thin film materials. A miniature tensile stage was developed in common with DEBEN UK for the mechanical characterization of functional thin film materials like PZT and ZnO ceramics, which are commonly used in MEMS fabrication. The stage is of- fered with a piezo electric motor which can be fitted with interchangeable heads. These can be combined with di.erent types of mounting jaws, enabling both con- ventional tensile testing and compression testing to be performed. Strains and displacements were measured in- situ using an optical, non destructive method based on CCD imaging. The elastic constants of polymer (LCP), LCP-Au bi- layers and electroplated Ni were defined in good agreement with the literature. However yield of successfully released ceramic samples was rather poor so a col- laboration with IMTEK at Germany was established. Using their facilities batch processing of a large number of wafers was possible. Cont/d.
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Gokhale, Nikhil Suresh. "Studies On The Development Of Piezoelectric Thin Flm Based Impact Sensor." Thesis, 2008. https://etd.iisc.ac.in/handle/2005/770.
Full textAbstract:
Sensors is one of the major areas of current research. Thin film micro/nano sensors are gaining attention worldwide, as there is necessity of miniaturization. There are varieties of sensors available by utilizing different materials in bulk and thin film form for measuring parameters like temperature, pressure, flow, humidity etc. Apart from these, there are various sensors available to measure impact force.
Impact sensor offers potential application possibilities in robotics, aerospace, structural & mechanical engineering and related areas. Many physical principles have been explored for the realization of impact sensor. The present thesis reports the efforts made in developing impact sensor using piezoelectric thin film. The necessary brief background information on impact sensors is presented in Chapter 1. This includes the description of available literature on impact sensors and their probable applications. In Chapter 2, a review of the various techniques such as thin film deposition techniques, film thickness measurement techniques, thin film characterization techniques, used in our work are explained in detail. Chapter 3 explains the direct and indirect methods of characterization used for confirming the piezoelectric property of zinc oxide thin films. The detailed experimental work carried out in realizing the impact sensor using piezoelectric thin films is presented in chapter 4. This includes design of the sensor, calibration setup used & the procedure followed and results obtained.
Finally, we present the summary of the work carried out in the thesis, conclusions arrived at and the scope for carrying out further work in the direction of making the sensor more efficient.
50
Gokhale, Nikhil Suresh. "Studies On The Development Of Piezoelectric Thin Flm Based Impact Sensor." Thesis, 2008. http://hdl.handle.net/2005/770.
Full textAbstract:
Sensors is one of the major areas of current research. Thin film micro/nano sensors are gaining attention worldwide, as there is necessity of miniaturization. There are varieties of sensors available by utilizing different materials in bulk and thin film form for measuring parameters like temperature, pressure, flow, humidity etc. Apart from these, there are various sensors available to measure impact force.
Impact sensor offers potential application possibilities in robotics, aerospace, structural & mechanical engineering and related areas. Many physical principles have been explored for the realization of impact sensor. The present thesis reports the efforts made in developing impact sensor using piezoelectric thin film. The necessary brief background information on impact sensors is presented in Chapter 1. This includes the description of available literature on impact sensors and their probable applications. In Chapter 2, a review of the various techniques such as thin film deposition techniques, film thickness measurement techniques, thin film characterization techniques, used in our work are explained in detail. Chapter 3 explains the direct and indirect methods of characterization used for confirming the piezoelectric property of zinc oxide thin films. The detailed experimental work carried out in realizing the impact sensor using piezoelectric thin films is presented in chapter 4. This includes design of the sensor, calibration setup used & the procedure followed and results obtained.
Finally, we present the summary of the work carried out in the thesis, conclusions arrived at and the scope for carrying out further work in the direction of making the sensor more efficient.