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Bathurst, Stephen 1980. "Ink jet printing of PZT thin films for MEMS." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78236.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 108-113).
Of the readily available piezoelectric engineering materials perovskite phase lead zirconate titanate (PZT) has the strongest mechanical to electrical coupling. PZT based devices have the potential to have the highest performance. Due to the strong piezoelectric response and low operating voltage, many groups have worked to integrate thin film PZT into a wide range of microelectromechanical systems (MEMS) devices including: actuators, energy harvesters, resonators, pressure sensors, pumps, nano-positioning stages, and MEMS switches. However, processing of thin film PZT is not readily compatible with existing MEMS fabrication processes and significant design constraints exist when integrating thin film PZT. In recent years drop-on-demand (DOD) printing has been studied as a robust, flexible, and inexpensive method of material deposition for MEMS. Direct printing enables the designer to deposit a film based on a digital pattern file only eliminating the need for photolithography and subsequent etching steps in the manufacturing process flow. There is a significant cost savings due to a reduction in the material consumption during manufacturing and in chemical waste produced. The result is a manufacturing process that is cleaner and cheaper than other common deposition techniques. The most compelling benefit of direct printing of PZT is that it provides a freedom of geometry that eliminates many of the design constraints currently associated with PZT MEMS. Since high quality thin films can be achieved with deposition control that is not possible with spin coating, novel functionalities can be incorporated into PZT MEMS. Specifically, PZT printing is able to deposit material over and around large out-of-plane features. In addition, the thickness of thin film PZT can vary deterministically across a device or across a wafer. A new manufacturing method for the deposition of PZT thin films based on ink jet printing has been developed and used to fabricate a piezoelectric micromachined ultrasonic transducer. A solvent system and processes parameters were established that enable the deposition of high quality PZT thin films. Substrate temperature and drop spacing for uniform deposition were determined and both multilayer and single layer PZT films were successfully deposited. Alignment within 10[mu]m and a resolution limit of 30[mu]m were demonstrated. The performance of a printed PZT based ultrasonic transducer was fit to established models to determine piezoelectric coupling and dielectric properties. The piezoelectric coupling coefficient, d₃₁, for printed PZT was between -75pC/N and -95pC/N. Impedance data at 1kHz provided the relative permittivity (750-890) and the dielectric loss tangent (2.4%-2.8%). The final printing process enabled the first digital deposition of thin film PZT and the printed PZT based pMUT confirmed the properties of the film are within the range required for a high performance piezoelectric MEMS devices.
by Stephen P. Bathurst.
Ph.D.
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Li, Jiantong. "Ink-jet printing of thin film transistors based on carbon nanotubes." Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-24427.
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The outstanding electrical and mechanical properties of single-walled carbon nanotubes (SWCNTs) may offer solutions to realizing high-mobility and high-bendability thin-film transistors (TFTs) for the emerging flexible electronics. This thesis aims to develop low-cost ink-jet printing techniques for high-performance TFTs based on pristine SWCNTs. The main challenge of this work is to suppress the effects of “metallic SWCNT contamination” and improve the device electrical performance. To this end, this thesis entails a balance between experiments and simulations. First, TFTs with low-density SWCNTs in the channel region are fabricated by utilizing standard silicon technology. Their electrical performance is investigated in terms of throughput, transfer characteristics, dimensional scaling and dependence on electrode metals. The demonstrated insensitivity of electrical performance to the electrode metals lifts constrains on choosing metal inks for ink-jet printing. Second, Monte Carlo models on the basis of percolation theory have been established, and high-efficiency algorithms have been proposed for investigations of large-size stick systems in order to facilitate studies of TFTs with channel length up to 1000 times that of the SWCNTs. The Monte Carlo simulations have led to fundamental understanding on stick percolation, including high-precision percolation threshold, universal finite-size scaling function, and dependence of critical conductivity exponents on assignment of component resistance. They have further generated understanding of practical issues regarding heterogeneous percolation systems and the doping effects in SWCNT TFTs. Third, Monte Carlo simulations are conducted to explore new device structures for performance improvement of SWCNT TFTs. In particular, a novel device structure featuring composite SWCNT networks in the channel is predicted by the simulation and subsequently confirmed experimentally by another research group. Through Monte Carlo simulations, the compatibility of previously-proposed long-strip-channel SWCNT TFTs with ink-jet printing has also been demonstrated. Finally, relatively sophisticated ink-jet printing techniques have been developed for SWCNT TFTs with long-strip channels. This research spans from SWCNT ink formulation to device design and fabrication. SWCNT TFTs are finally ink-jet printed on both silicon wafers and flexible Kapton substrates with fairly high electrical performance.QC 20100910
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Fang, Mei. "Properties of Multifunctional Oxide Thin Films Despostied by Ink-jet Printing." Doctoral thesis, KTH, Teknisk materialfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102021.
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Ink-jet printing offers an ideal answer to the emerging trends and demands of depositing at ambient temperatures picoliter droplets of oxide solutions into functional thin films and device components with a high degree of pixel precision. It is a direct single-step mask-free patterning technique that enables multi-layer and 3D patterning. This method is fast, simple, easily scalable, precise, inexpensive and cost effective compared to any of other methods available for the realization of the promise of flexible, and/or stretchable electronics of the future on virtually any type of substrate. Because low temperatures are used and no aggressive chemicals are required for ink preparation, ink-jet technique is compatible with a very broad range of functional materials like polymers, proteins and even live cells, which can be used to fabricate inorganic/organic/bio hybrids, bio-sensors and lab-on-chip architectures. After a discussion of the essentials of ink-jet technology, this thesis focuses particularly on the art of designing long term stable inks for fabricating thin films and devices especially oxide functional components for electronics, solar energy conversion, opto-electronics and spintronics. We have investigated three classes of inks: nanoparticle suspension based, surface modified nanoparticles based, and direct precursor solution based. Examples of the films produced using these inks and their functional properties are: 1) In order to obtain magnetite nanoparticles with high magnetic moment and narrow size distribution in suspensions for medical diagnostics, we have developed a rapid mixing technique and produced nanoparticles with moments close to theoretical values (APL 2011 and Nanotechnology 2012). The suspensions produced have been tailored to be stable over a long period of time. 2)In order to design photonic band gaps, suspensions of spherical SiO2 particles were produced by chemical hydrolysis (JAP 2010 and JNP 2011 - not discussed in the thesis). 3) Using suspension inks, (ZnO)1-x(TiO2)x composite films have been printed and used to fabricate dye sensitized solar cells (JMR 2012). The thickness and the composition of the films can be easily tailored in the inkjet printing process. Consequently, the solar cell performance is optimized. We find that adding Ag nanoparticles improves the ‘metal-bridge’ between the TiO2 grains while maintaining the desired porous structure in the films. The photoluminescence spectra show that adding Ag reduces the emission intensity by a factor of two. This indicates that Ag atoms act as traps to capture electrons and inhibit recombination of electron-hole pairs, which is desirable for photo-voltaic applications. 4) To obtain and study room temperature contamination free ferromagnetic spintronic materials, defect induced and Fe doped MgO and ZnO were synthesized ‘in-situ’ by precursor solution technique (preprints). It is found that the origin of magnetism in these materials (APL 2012 and MRS 2012) is intrinsic and probably due to charge transfer hole doping. 5) ITO thin films were fabricated via inkjet printing directly from liquid precursors. The films are highly transparent (transparency >90% both in the visible and IR range, which is rather unique as compared to any other film growth technique) and conductive (resistivity can be ~0.03 Ω•cm). The films have nano-porous structure, which is an added bonus from ink jetting that makes such films applicable for a broad range of applications. One example is in implantable biomedical components and lab-on-chip architectures where high transparency of the well conductive ITO electrodes makes them easily compatible with the use of quantum dots and fluorescent dyes. In summary, the inkjet patterning technique is incredibly versatile and applicable for a multitude of metal and oxide deposition and patterning. Especially in the case of using acetate solutions as inks (a method demonstrated for the first time by our group), the oxide films can be prepared ‘in-situ’ by direct patterning on the substrate without any prior synthesis stages, and the fabricated films are stoichiometric, uniform and smooth. This technique will most certainly continue to be a versatile tool in industrial manufacturing processes for material deposition in the future, as well as a unique fabrication tool for tailorable functional components and devices.QC 20120907
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Okabayashi, Y., K. kanai, Y. Ouchi, K. Seki, and 一彦 関. "Apparatus for solution jet beam deposition of organic thin films and in situ ultraviolet photoelectron spectroscopy." American Institute of Physics, 2006. http://hdl.handle.net/2237/7048.
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Mendez, Miguel Alfonso. "Dynamics of Gas Jet Impinging on Falling Liquid Films." Doctoral thesis, Universite Libre de Bruxelles, 2018. https://dipot.ulb.ac.be/dspace/bitstream/2013/281945/5/contratMM.pdf.
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This thesis describes the unstable dynamics of a gas jet impinging on a falling liquid film. This flow configuration is encountered in the jet wiping process, used in continuous coating applications such as the hot-dip galvanizing to control the thickness of a liquid coat on a moving substrate. The interaction between these flows generates a non-uniform coating layer, of great concern for the quality of industrial products, and results from a complex coupling between the interface instabilities of the liquid film and the confinement-driven instabilities of the impinging jet.Combining experimental and numerical methods, this thesis studied the dynamics of these flows on three simplified flow configurations, designed to isolate the key features of their respective instabilities and to provide complementary information on their mutual interaction. These configurations include the gas jet impingement on a falling liquid film perturbed with controlled flow rate pulsation, the gas jet impingement on a solid interface reproducing stable and unstable liquid film interfaces and a laboratory scaled model of the jet wiping process. Each of these configurations was reproduced on dedicated experimental set-up, instrumented for non-intrusive measurement techniques such as High-Speed Flow Visualization (HSFV) and Time-resolved Particle Image Velocimetry (TR-PIV) for the gas jet flow analysis, Laser Induced Fluorescence (LIF) tracking of the liquid interface, and 3D Light Absorption (LAbs) measurement of the liquid film thickness. To optimize the performances of these measurement techniques, several advanced data processing routines were developed, including a novel image pre-processing method for background removal in PIV and a dynamic feature tracking for the automatic detection of the jet flow and the liquid film interface from HSFV, LIF, and PIV videos.To identify the flow structures driving the unstable response of the jet flow, a novel data-driven modal decomposition was developed. This decomposition, referred to as Multiscale Proper Orthogonal Decomposition (mPOD), was validated on synthetic, numerical and experimental test cases and allowed for better feature extraction than classical alternatives such as Proper Orthogonal Decomposition (POD) or Dynamic Mode Decomposition (DMD).The experimental work on these laboratory models was complemented with the analysis of several numerical simulations, including a classical 2D Unsteady Reynolds Averaged Navier Stokes (URANS) modeling of the gas jet impingement on a fixed interface, a 2D Variational Multiscale Simulation (VMS) with anisotropic mesh refinement of the gas jet impingement on a pulsing interface, and a 3D simulation of the jet wiping process combining Large Eddy Simulation (LES) on the gas side with Volume of Fluid (VOF) treatment of the liquid film flow. The experimental modal analysis on the dynamic response of the gas jet and the characterization of the pressure-velocity coupling in the numerical investigation allowed for a complete picture of the mechanism driving the jet oscillation and its possible impact on the liquid film.In parallel, several flow control strategies to prevent the jet oscillation were developed, tested numerically and experimentally in simplified conditions, and later implemented on the design of a new nozzle for the jet wiping process. This new nozzle was finally tested on a laboratory scale of the wiping process and its performances compared to single jet and multiple jet wiping configurations. In these three cases, the experimental work presents the modal analysis of the gas field using TR-PIV and mPOD, the liquid interface tracking via LIF, and the final coating thickness characterization via LAbs.The large spatiotemporally resolved experimental database allowed to give a detailed description of the jet wiping instability and to provide new insights on this fascinating fundamental and applied problem of fluid dynamics.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Mishra, Nilesha [Verfasser]. "Influence of strain on the functionality of ink-jet printed thin films and devices on flexible substrates / Nilesha Mishra." Karlsruhe : KIT Scientific Publishing, 2019. http://www.ksp.kit.edu.
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Mishra, Nilesha [Verfasser]. "Influence of strain on the functionality of ink-jet printed thin films and devices on flexible substrates / Nilesha Mishra." Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1166234304/34.
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Rajendran, Sucharitha. "Investigation of Drop Generation from Low Velocity Liquid Jets and its Impact Dynamics on Thin Liquid Films." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1512038966865923.
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Sahay, Prateek. "Development of a Robotic Cell for Removal of Tabs from Jet Engine Turbine Blade." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1574417686354007.
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Drahi, Etienne. "Impression de silicium par procédé jet d’encre : des nanoparticules aux couches minces fonctionnelles pour applications photovoltaïques." Thesis, Saint-Etienne, EMSE, 2013. http://www.theses.fr/2013EMSE0685/document.
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Cette étude prend place dans le cadre du projet ANR Inxilicium visant à la réalisation de cellules solaires en couches minces de silicium par jet d’encre. Les nanoparticules de silicium sont des matériaux à fort potentiel pour la levée de verrous technologiques grâce à leurs propriétés spécifiques. Des encres de nanoparticules de Si issues de diverses méthodes de synthèse ont été imprimées par jet d’encre sur différents substrats : quartz, électrodes métalliques (aluminium, molybdène) et transparente conductrice (ZnO:Al). L’optimisation du procédé d’impression, de l’interaction encre/substrat (via la modulation de l’énergie de surface des substrats) et de l’étape de séchage a permis l’obtention de couches minces homogènes et continues (plusieurs centaines de nm à quelques µm d’épaisseur)A posteriori, une étape de recuit est nécessaire pour recouvrer des propriétés fonctionnelles. L’utilisation de nanoparticules à la physico-chimie de surface contrôlée fait décroître les températures de frittage de 1100 °C à environ 600 °C. En complément, des recuits sélectifs (micro-ondes et photonique) ont été évalués pour leur application sur des substrats flexibles et bas coûts.Les propriétés optiques et les interfaces électrode/silicium ont été examinées afin d’intégrer ces couches dans des dispositifs (cellule solaire…). La formation de transitions métallurgiques Al-Si et Mo-Si a été étudiées par DRX-in situ. L’ensemble de ces travaux a permis la réalisation d’une jonction PN montrant un comportement photovoltaïque à fort champ grâce aussi à la mise au point d’une méthode innovante de collage ouvrant la voie à une réduction du bilan thermique des procédés de fabricationThis study takes place in the frame of the Inxilicium project from the National Research Agency, which targets the fabrication of silicon thin film solar cells by inkjet-printing. Thanks to their specific properties, silicon nanoparticles are materials with strong potential for technological breakthroughs. Silicon nanoparticle-based inks made by different synthesis routes have been inkjet-printed on different substrates: quartz, metallic electrodes (aluminum, molybdenum) and transparent electrodes (ZnO:Al). Homogeneous and continuous thin films (from several hundreds of nm to some µm thick) have been obtained through optimization of the printing process, the ink/substrate interaction (via substrates surface energy tuning) and the drying step.A posteriori, an annealing step is mandatory for recovering of functional properties. By using nanoparticles with tailored surface physical chemistry, the sintering temperature decreases from 1100 °C to 600 °C. In order to allow the use of this material on flexible and low cost substrates, selective sintering (microwave and photonics) have been also evaluated.Thin film optical properties and electrode/silicon interfaces have been investigated with the purpose to integrate those layers into devices (solar cells…). Metallurgical evolution of Al-Si and Mo-Si physical interfaces has been studied by in situ XRD.This work allowed the fabrication of a PN junction with a photovoltaic behaviour under strong polarization voltage thanks to the development of an innovative thermal pasting process, which opens the way to the reduction of process thermal budget
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Talagrand, Clément. "Transistor en couches minces avec canal en oxyde d’indium de gallium et de zinc : matériaux, procédés, dispositifs." Thesis, Saint-Etienne, EMSE, 2015. http://www.theses.fr/2015EMSE0797/document.
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Pour réaliser des fonctions électroniques sur support souple, le transistor en couches minces (TFT) est indispensable. Cette thèse a pour objectif d’approfondir les connaissances sur ces dispositifs.L’état de l’art est synthétisé dans le chapitre 1. Cette partie présente tout d’abord les TFT et justifie l’utilisation de l’oxyde d’indium gallium zinc (IGZO). Ensuite les propriétés de cet oxyde semi-conducteur amorphe sont traitées ; et enfin le chapitre fait état des résultats obtenus avec des TFT en IGZO.Le chapitre 2 établie un lien entre les propriétés de l’IGZO et le dépôt par pulvérisation cathodique. L’étude des films a été réalisée par ellipsométrie spectroscopique. Celle-ci a mis en évidence des variations dans les propriétés optiques dues au temps de dépôt, à la concentration en oxygène et à la position sur le substrat. Ces résultats ont été comparés à des mesures de résistivité, pour comprendre plus précisément la cause de ces variations.Le chapitre 3 élabore un procédé complet permettant de réaliser des TFT sur support souple. Le choix des différents matériaux est discuté, et les différents outils de procédés sont adaptés afin de réaliser ces dispositifs. Les TFT obtenus sont caractérisés en fonction du temps de recuit et sous flexion. Ils ont atteint des mobilités 10 cm².V-1.s-1.Le chapitre 4 étudie le dépôt d’IGZO par impression jet d’encre. Une encre a été formulée et les différents paramètres d’impression ajustés. Afin de comparer les différentes techniques de dépôt, des TFT avec canal en IGZO imprimé ont été réalisé et les films imprimés ont été caractérisé par ellipsométrie spectroscopique. Ces dispositifs ont atteint des mobilités de 0,4 cm2.V-1.s-1In order to carry out electronics functions on flexible substrate, thin film transistor is essential. The aim of this thesis is to increase knowledge on this device.State of art of IGZO TFT is summarized in chapter 1. This part presents thin film transistor and justify the choice of IGZO as the semiconductor material. Then, properties of this amorphous oxide semiconductor are discussed. Finally, this chapter presents the results obtained in the literature for IGZO based thin film transistor.Chapter 2 establishes a link between IGZO properties and sputtering deposition. Films are studied by spectroscopic ellipsometry. Experiments show variations in optical properties due to deposition time, oxygen content and position on the wafer. Resistivity measurements are carried out to understand more deeply the causes of these variations.Chapter 3 develops a complete process to achieve TFT on flexible substrate. The choice of different materials and processes is discussed. The performances of the TFT are investigated versus the annealing time and characterized under mechanical stress. Mobility up to 10 cm2.V-1.s-1 can be achieved after an annealing at 300°C during 1h30. Mechanical stresses show a degradation of the transistor induced by cracks in the oxide layer.Chapter 4 focuses on IGZO's deposition by inkjet printing. An ink is formulated using metallic salts and a solvents mixture. The parameters of the printing system are also optimized. To compare the different techniques of deposition, printed IGZO TFTs are characterized and compared with the one fabricated with the standard PVD deposition technique. Mobility is relatively lower and equals 0.4 cm2.V-1.s-1
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Kintz, Harold. "Réalisation de couches minces nanocomposites par un procédé original couplant la pyrolyse laser et la pulvérisation magnétron : application aux cellules solaires tout silicium de troisième génération." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00958453.
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Ce travail porte sur la synthèse de couches minces de nanoparticules de silicium (np-Si) encapsulées dans une matrice diélectrique en vue d'une application en tant que couche active pour les cellules solaires de 3ème génération. La technique utilisée pour la synthèse des np-Si est la pyrolyse laser. Cette technique nous a permis d'obtenir des np-Si cristallines d'environ 5 nm de diamètre avec une distribution en taille étroite. Par ailleurs, l'utilisation de gaz précurseurs spécifiques (PH₃, B₂H₆) dans le mélange réactionnel a rendu possible le dopage (type n ou p) des np-Si. Le dopage effectif des np-Si a pu être mis en évidence par des mesures de résonance paramagnétique électronique (RPE). Des films de np-Si seules ont pu être déposés in-situ via la création d'un jet supersonique de gaz contenant les particules de silicium. Les caractérisations optoélectroniques de ces couches ont montré un effet de confinement quantique fort au sein de films, garantissant ainsi un élargissement important du gap du silicium de 1.12 eV (pour le silicium massif) à environ 2 eV (pour les np-Si) ; prérequis indispensable pour réaliser une cellule tandem tout silicium. Des mesures de résistivité sur ces films ont permis de confirmer l'activité des dopants au sein des np-Si. Pour les np-Si dopées au phosphore une diminution de la résistivité de plus de 5 ordres de grandeurs par rapport au np-Si intrinsèques a été observée. Le couplage entre la pyrolyse laser et la pulvérisation magnétron via notre dispositif original de synthèse s'est révélé parfaitement adapté à l'élaboration de couches minces nanocomposites np-Si/SiO₂. Un comportement de type diode a pu être mis en évidence sur une jonction constituée par la superposition d'une couche nanocomposites (type n) sur un substrat de silicium massif (type p). Au-delà de la simple application au photovoltaïque, le procédé couplé, largement éprouvé et optimisé au cours de ce travail de thèse, pourrait permettre la réalisation d'une multitude de couches nanocomposites différentes, puisque la nature chimique des particules et de la matrice peuvent être choisies indépendamment.
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Martini, Thibaut. "Etude de la formulation d'encre à base de précurseurs Cu, Zn, Sn, S et du recuit de cristallisation pour le dépot hors vide de couches photovoltaïques." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI063/document.
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Les kësterites, ou Cu2ZnSn(S,Se)4 (CZTS), sont des matériaux semi-conducteurs composés uniquement d'éléments abondants. Leur gap direct compris entre 1.0 et 1.5 eV en fait d'excellents candidats pour remplacer les absorbeurs actuellement utilisés en couches minces. Ce travail de thèse décrit la fabrication de couches minces de Cu2ZnSnS4 par impression de nanoparticules suivie d'un recuit de cristallisation. Différentes synthèses hydrothermales de nanoparticules ont été développées, dont certaines en réacteur à flot continu, en vue d'un développement à plus grande échelle. L'influence des types de précurseurs et des conditions de synthèse sur la composition chimique des particules est étudiée ainsi que leur pureté est évaluée. Le comportement en dispersion colloïdale est ensuite caractérisé et trois fonctionnalisations de surfaces à base de dodecanthiol, dodecyl pyrrolidone et anions sulfures sont présentées. Ces stabilisations permettent la fabrication d'encre jet d'encre et spray adaptées au dépôt sur molybdène. Les couches imprimées et séchées sont recuites sous atmosphère de soufre. Des recuits d'au moins 120 minutes sont nécessaires. Cependant la croissance des couches est hétérogène lorsque celles-ci sont imprimées avec les nanoparticules stabilisées par le dodecanethiol et le dodecyl pyrrolidone. La présence de carbone dans les couches, identifiable par spectroscopie Raman, inhibe la croissance du matériau. Seules les couches minces imprimées à l'aide de nanoparticules purifiées et stabilisées par anions sulfures permettent la croissance homogène du matériau lors du recuitKësterites or Cu2ZnSn(S,Se)4 (CZTS), are semi-conductors only made of abundant elements. Their direct bangap between 1.0 and 1.5 eV makes them excellent candidates for the replacement of the currently used thin film absorbers. This thesis describes the fabrication of thin films of Cu2ZnSnS4 by nanoparticles printing followed by crystallization annealing. Different hydrothermal synthesis of nanoparticles have been developed, some in continuous flow reactor, for a development on a larger scale. The influence of the types of precursors and synthesis conditions on the particals chemical composition purity was evaluated. The behavior of colloidal dispersion is then characterized and three surface functionalization based on dodecanthiol, dodecyl pyrrolidone and sulfide anions are presented. These stabilizations allow the manufacture of inks deposited by inkjet and spray on molybdenum. The printed and dried layers are then annealed in sulfur atmosphere. Annealing of at least 120 minutes are required. However, the growth of the layers is heterogeneous when printed with the nanoparticles stabilized by dodecanethiol and dodecyl pyrrolidone. The presence of high carbon content, prooved by Raman spectroscopy, inhibits the growth of the material. Only thin film printed using purified nanoparticles stabilized by sulfide anions allow homogeneous growth of the material during annealing
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Ralph, Elise Ann. "Predicting eddy detachment from thin jets." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/54968.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences and Woods Hole Oceanographic Institute, 1991.Bibliography: p. 103-105.
by Elise Ann Ralph.
M.S.
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Moon, Seung Jae. "Development of inkjet printing technology for fully solution process dedicated to organic electronic circuits." Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S009.
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L’objectif de cette thèse était de démontrer les potentialités du procédé technologique d’impression jet d’encre pour la fabrication de circuits numériques à base de matériaux organiques. Une première étape sur le développement d’une structure de transistor couches minces organiques (OTFTs) fabriquée par impression jet d’encre a permis d’appréhender les mécanismes d’intéraction entre les différents matériaux déposés en solution. A partir de cette étude, la structure a pu être optimisée afin d’obtenir des performances électriques uniformes et reproductibles. Les transistors en couches minces organiques ont ensuite été modélisés électriquement à l’aide d’un modèle simple (Aim-Extract, Aim-Spice). La comparaison entre caractérisations et simulations électriques ont démontré la possibilité de prédire le comportement électrique de la structure OTFT imprimée.A partir de ce modèle, des portes logiques élémentaires ont été simulées puis fabriquées par la technologie d’impression jet d’encre. Les limitations en termes de temps de réponse des circuits et de tensions d’alimentation ont ainsi pu être déterminés. Finalement, des circuits électroniques combinatoires et séquentiels plus complexes, tel que des multiplexeurs et des bascules de type D, ont été fabriqués et caractérisés. La démarche employée au cours de cette étude, à savoir, l’optimisation de la structure OTFT, la modélisation électrique et la fabrication d’un circuit électronique complet a démontré les potentialités de l’impression jet d’encre pour la réalisation d’électronique bas-coût, grande surface, entièrement additive et potentiellement flexibleThe main objective of this study was to demonstrate the capability of inkjet printing technology to fabricate organic based digital circuits. At first, development of an Organic Thin Film Transistor structure (OTFTs) fabricated with inkjet printing technology has highlighted interaction mechanisms between materials deposited with a fully solution process. From this study, the structure has been optimized to obtain uniform and reproducible electrical performance. The organic Thin Film Transistors were then electrically modeled using a simple model (Aim-Extract, Aim-Spice). The comparison between electrical characterizations and simulations has demonstrated the possibility to predict electrical behavior of printed OTFT. From this model, elementary logic gates were simulated and then fabricated by inkjet printing technology. Time response and supply voltage of such circuit has been determined. Finally, more complex combinational and sequential electronic circuits, such as multiplexers and D-latch, were fabricated and characterized. The Experimental protocol used in this study dealing with: i) OTFT electrical optimization, ii) electrical modeling and iii) electronic circuit fabrication has demonstrated the ability of inkjet printing to reach low-cost, large area, fully additive and potentially flexible electronics
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Pickworth, Louisa Alyce. "Experimental investigation of supersonic plasma jets colliding with thin metallic foils." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/15670.
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An experimental investigation of collisions between supersonic plasma jets with metal foils and head-on collisions of two jets will be presented. The jets are produced by ablation of thin aluminium foils driven by 1.4MA, 250ns current pulse in a radial foil Z-pinch configuration. The jets propagate with velocity of 50-100km/s, showing a high degree of collimation (opening angle 2 [degrees] to 5 [degrees]) and are radiatively cooled (cooling time << hydrodynamic times). Collisions of the jets with foils, as well as inter-jet collisions, create a system of strong shocks both in the central dense part of the jet and in the lower density halo plasma which surrounds the jet and moves with the same speed. The formed shock features are sustained for 300ns, and are diagnosed with laser interferometry, optical and XUV imaging, and Thomson scattering diagnostics. Interpretation of the results indicates that dynamically significant magnetic fields are present in the system, balancing the ram pressure of the flow and supporting extended stationary shock structures. The results are relevant to the studies of astrophysical phenomena in the laboratory, in particular internal shocks in jets from young stars, accretion shocks, and for the understanding of magnetised high energy density plasma flows.
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Le, Druillennec Marie. "Etude des mécanismes d'endommagement de films minces métalliques déposés sur substrats souples pour l'électronique flexible." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI108/document.
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Depuis une vingtaine d'années, des composants électroniques flexibles sont développés. Ces composants étant amenés à se tordre, à s'étirer et à se fléchir au cours de leur utilisation, le développement de composants ayant une bonne fiabilité mécanique est primordial. Ce travail s'est concentré sur les films métalliques d'argent déposés par impression jet d'encre ou sérigraphie sur des substrats de polyimide, servant à l’interconnexion électrique entre composants actifs. Deux mécanismes d’endommagement sont observables dans ces systèmes : la fissuration et le flambement par délaminage.Premièrement, pour caractériser expérimentalement ces deux phénomènes, des tests de traction sont réalisés sous microscope optique, afin de suivre l'évolution des fissures au cours de la déformation et sous interféromètre optique, afin de suivre les cloques de délaminage. Une analyse d'images est réalisée afin d'obtenir l'évolution de l'espacement entre fissures au cours de la déformation. L'existence de deux régimes de fissuration est observée : la fissuration longue et droite pour les films épais et la fissuration courte et en forme de zigzag pour les films minces. Le suivi des profils de cloques permet d'obtenir l'évolution de leur forme au cours de la déformation.Ensuite, afin d'éclairer les observations expérimentales, les phénomènes à l'étude sont modélisés par élément finis. Ainsi l'origine des deux régimes de fissuration est expliquée par un effet géométrique de l'épaisseur du film. Un modèle élastoplastique bidimensionnel de relaxation de contraintes dans le film permet d'obtenir un encadrement de l'espacement entre fissures au cours de la déformation. À partir du suivi des cloques, un modèle tridimensionnel permet de réaliser une identification des paramètres de la zone cohésive à l'interface film/substrat, où une énergie d'adhésion de 2 J.m-2, une contrainte critique de 20 MPa et un paramètre de mixité modale de 0,4 sont déterminés. Ces valeurs sont en accord avec la littératureOver the past 20 years, new improvements in materials and processes led to the development of printed flexible electronics. Flexible electronics devices subjected to bending, twisting, or stretching during their lifetime, the development of device with high reliability is therefore of great importance for the efficiency of electrical connection. This work investigates the mechanical reliability of inkjet or screen-printed Ag thin films on polyimide substrates dedicated to the electrical interconnection of active components. Expected mechanical failure modes are film cracking and buckling delamination.First of all, in order to characterized the two mechanisms, tensile tests are performed under an optical microscope to follow cracks and under an optical interferometer to follow buckles. In order to obtain crack spacing evolution during deformation, an image processing is realized. Two types of cracks are observed: long and straight cracking for thick films and small and zigzag shape cracking for thin films. The evolution of buckles shape with imposed tensile deformation is characterized.In a second time, in order to understand experimental observations, mechanical failure modes are analysed with finite elements models. The origin of the two types of cracking are explained by a geometrical effect of film thickness. A elastoplastic shear lag bidimensional model gives upper and lower bonds of crack spacing during deformation. A three-dimensional model allows identification of cohesive zone model parameters at film/substrate interface, from experimental buckle shape. An adhesion energy of 2 J.m-2 , a critical strength of 20 MPa and a mode mixity parameter of 0.4 are determined. These values are in good agreement with literature
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Hahn, Nielsen Jennifer Helene. "What Drove This Painted Wood Together." Bowling Green State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1522331756842806.
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Takeda, Yuya. "More than a tape-recorder : negotiations of English language teacher identities in the JET Program in Japan." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62593.
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The Japan Exchange and Teaching Programme (JET Programme) is currently one of the largest government-sponsored programs for recruiting English language teachers in the world (Nagatomo, 2016). This year, 2017, marks the 30th anniversary since its launch, and the Japanese government has announced its plan to expand the scale of the program as a response to globalization (Uemura, Urabayashi, & Emoto, 2014). While the JET Programme’s contribution to the internationalization of the Japanese education system has been recognized (McConnell, 2000), scholars have also pointed out a number of issues within the JET Programme, such as lack of inclusion of assistant language teachers (ALTs) (McConnell, 2000), frequent miscommunications between Japanese teachers of English (JTEs) and ALTs (Muroi & Mochizuki, 2010), reinforcement of the perceived superiority of English over other languages (Kubota, 2002), and reinforcement of the essentialist view of culture (Kobayashi, 2011). However, few studies have investigated how the identities of ALTs are assigned, negotiated, and resisted.
Through Gee’s (2014) D/discourse analysis, this study investigates how six ALTs construct their teacher identity—the way in which they come to understand themselves as teachers—during the program. This study highlights how issues within the JET Programme, such as the ones listed above, are discursively (re)produced. Drawing on Gee’s (2015) notion of Discourse (with a capital D), this study pays particular attention to how ALTs participate in the meaning-making practice in their schools’ community. Data were collected through semi-structured interviews conducted over Skype.
Fine-grained analysis of discourse illuminates the interaction between the macro-level discourse (i.e., nihonjinron [theory of Japaneseness] and kokusaika [internationalization]) and language ideology (i.e., “monolingual bias”; Kachru, 1994), the meso-level structure of the JET Programme, and the micro-level practices at participants’ schools. The findings show various ways in which ALTs struggled to attain membership in their schools’ Discursive community due to their racial, gender, linguistic, and employment statuses. Even those who successfully attained a certain level of membership in their schools’ Discourses were under constant fear of delegitimatization because of their marked foreignness. Based on the findings, this study offers implications for the JET Programme and advocates macro-, meso-, and micro-level changes.Education, Faculty of
Language and Literacy Education (LLED), Department of
Graduate
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Rioult, Maxime. "Hematite-based epitaxial thin films as photoanodes for solar water splitting." Palaiseau, Ecole polytechnique, 2015. https://theses.hal.science/tel-01220396/document.
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Utiliser l'hydrogène en tant que vecteur énergétique pour stocker l'énergie solaire et/ou remplacer le pétrole comme carburant est très attrayant, d'autant qu'il peut être produit de façon propre par photo-électrolyse de l'eau. Dans ce procédé, des paires électron-trou, générées par éclairement dans des semi-conducteurs immergés dans une solution aqueuse, réalisent les réactions d’oxydo-réduction de l’eau (production d'oxygène à la photo-anode et production d'hydrogène à la photo-cathode). Les oxydes de métaux de transition, en particulier l'hématite (α-Fe2O3) qui présente un gap quasi-idéal pour cette application, sont les matériaux de photo-anode les plus prometteurs. Des films minces d'hématite ont été déposés sur des monocristaux par épitaxie par jets moléculaires assistée par plasma d’oxygène. Ces échantillons modèles ainsi que l’utilisation de techniques de pointe, notamment utilisant le rayonnement synchrotron, rendent possible l’identification des paramètres pertinents influençant les propriétés de photo-électrolyse. Je me suis d'abord intéressé à l'impact de la structure cristallographique, de la stœchiométrie et de la morphologie de surface. Ensuite, les effets d'un dopage avec du titane ont été analysés, montrant l'existence d'un taux de dopage optimal et l'augmentation de la longueur de diffusion des porteurs de charges induisant un fort gain en photo-courant. J'ai également étudié la structure électronique et la dynamique des recombinaisons en surface d'hétérojonctions TiO2 - hématite dopée Ti, révélant une interface diffuse. Enfin, le champ électrique interne créé par un film mince ferroélectrique de BaTiO3/Nb:SrTiO3 a été considéré pour améliorer les propriétés des photo-anodes. Un premier pas vers la compréhension du lien entre polarisation ferroélectrique et photo-courant a été fait, mettant en évidence un champ électrique interne favorable pour séparer les chargesUsing hydrogen as an energy carrier for solar energy storage and/or fuel alternative to oil is very appealing, especially as it can be cleanly produced by solar water splitting. In this process, electron-hole pairs, generated in illuminated semiconductors dipped in an aqueous solution, realize the water oxidoreduction reactions (oxygen production at the photoanode and hydrogen production at the photocathode). Transition metal oxides, in particular hematite (α-Fe2O3) which features a quasi ideal band-gap for this application, are the most promising photoanodes materials. Hematite thin films were deposited on single crystals by oxygen plasma assisted molecular beam epitaxy. These model samples along with the use of high-end techniques, in particular using synchrotron radiation, make possible the identification of the relevant parameters affecting the photoelectrochemical properties. I firstly focused on the impact of the crystallographic structure, the stoichiometry and the surface morphology. Then the effects of doping with titanium were investigated, demonstrating the existence of an optimal doping level and an increase of the charges diffusion length inducing a high photocurrent gain. In addition, I studied the electronic structure and the surface recombinations dynamics of TiO2 - Ti-doped hematite heterojunctions, revealing a diffuse interface. Lastly, the internal electric field created by a ferroelectric thin film of BaTiO3/Nb:SrTiO3 was considered in order to enhance the performances of photoanodes. A first step toward the comprehension of the link between ferroelectric polarization and photocurrent was achieved through the evidence of an internal electric field favourable for the separation of charges
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Yin, Shi. "Integration of epitaxial piezoelectric thin films on silicon." Thesis, Ecully, Ecole centrale de Lyon, 2013. http://www.theses.fr/2013ECDL0039/document.
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Les matériaux piézoélectriques, comme le titanate-zirconate de plomb Pb(ZrxTi1-x)O3 (PZT), l’oxyde de zinc ZnO, ainsi que la solution solide de Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), sont actuellement l’objet d’études de plus en plus nombreuses à cause de leurs applications innovantes dans les systèmes micro-électromécaniques (MEMS). Afin de les intégrer sur substrat de silicium, certaines précautions doivent être prises en compte concernant par exemple des couches tampon, les électrodes inférieures. Dans cette thèse, des films piézoélectriques (PZT et PMN-PT) ont été épitaxiés avec succès sous forme de monocristaux sur silicium et SOI (silicon-on-insulator) par procédé sol-gel. En effet, des études récentes ont montré que les films piézoélectriques monocristallins semblent posséder des propriétés supérieures à celles des films polycristallins, permettant ainsi une augmentation de la performance des dispositifs MEMS. Le premier objectif de cette thèse était de réaliser l'épitaxie de film monocristallin de matériaux piézoélectriques sur silicium. L'utilisation d’une couche tampon d'oxyde de gadolinium (Gd2O3) ou de titanate de strontium (SrTiO3 ou STO) déposés par la technique d’épitaxie par jets moléculaires (EJM) a été explorée en détail pour favoriser l’épitaxie du PZT et PMN-PT sur silicium. Sur le système Gd2O3/Si(111), l’étude par diffraction des rayons X (XRD) de la croissance du film PZT montre que le film est polyphasé avec la présence de la phase parasite pyrochlore non ferroélectrique. Cependant, le film PZT déposé sur le système STO/Si(001) est parfaitement épitaxié sous forme d’un film monocristallin. Afin de mesurer ses propriétés électriques, une couche de ruthenate de strontium conducteur SrRuO3 (SRO) déposée par ablation laser pulsé (PLD) a été utilisée comme l'électrode inférieure à cause de son excellente conductibilité et de sa structure cristalline pérovskite similaire à celle du PZT. Les caractérisations électriques sur des condensateurs Ru/PZT/SRO démontrent de très bonnes propriétés ferroélectriques avec présence de cycles d'hystérésis. Par ailleurs, le matériau relaxeur PMN-PT a aussi été épitaxié sur STO/Si comme l’a confirmé la diffraction des rayons X ainsi que la microscopie électronique en transmission (TEM). Ce film monocristallin est de la phase de perovskite sans présence de pyrochlore. En outre, une étude en transmission du rayonnement infrarouge au synchrotron a prouvé une transition de phase diffuse sur une large gamme de température, comme attendue dans le cas d’un relaxeur. L'autre intérêt d'avoir des films PZT monocristallins déposés sur silicium et SOI est de pouvoir utiliser les méthodes de structuration du silicium bien standardisées maintenant pour fabriquer les dispositifs MEMS. La mise au point d’un procédé de micro-structuration en salle blanche a permis de réaliser des cantilevers et des membranes afin de caractériser mécaniquement les couches piézoélectriques. Des déplacements par l'application d'une tension électrique ont ainsi pu être détectés par interférométrie. Finalement, cette caractérisation par interférométrie a été combinée avec une modélisation basée sur la méthode des éléments finis. Dans le futur, il sera nécessaire d’optimiser le procédé de microfabrication du dispositif MEMS afin d’en améliorer les performances électromécaniques. Enfin, des caractérisations au niveau du dispositif MEMS lui-même devront être développées en vue de leur utilisation dans de futures applicationsRecently, piezoelectric materials, like lead titanate zirconate Pb(ZrxTi1-x)O3 (PZT), zinc oxide ZnO, and the solid solution Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), increasingly receive intensive studies because of their innovative applications in the microelectromechanical systems (MEMS). In order to integrate them on silicon substrate, several preliminaries must be taken into considerations, e.g. buffer layer, bottom electrode. In this thesis, piezoelectric films (PZT and PMN-PT) have been successfully epitaxially grown on silicon and SOI (silicon-on-insulator) in the form of single crystal by sol-gel process. In fact, recent studies show that single crystalline films seem to possess the superior properties than that of polycrystalline films, leading to an increase of the performance of MEMS devices. The first objective of this thesis was to realize the epitaxial growth of single crystalline film of piezoelectric materials on silicon. The use of a buffer layer of gadolinium oxide(Gd2O3) or strontium titanate (SrTiO3 or STO) deposited by molecular beam epitaxy (MBE) has been studied in detail to integrate epitaxial PZT and PMN-PT films on silicon. For Gd2O3/Si(111) system, the study of X-ray diffraction (XRD) on the growth of PZT film shows that the film is polycrystalline with coexistence of the nonferroelectric parasite phase, i.e. pyrochlore phase. On the other hand, the PZT film deposited on STO/Si(001) substrate is successfully epitaxially grown in the form of single crystalline film. In order to measure the electrical properties, a layer of strontium ruthenate (SrRuO3 or SRO) deposited by pulsed laser deposition (PLD) has been employed for bottom electrode due to its excellent conductivity and perovskite crystalline structure similar to that of PZT. The electrical characterization on Ru/PZT/SRO capacitors demonstrates good ferroelectric properties with the presence of hysteresis loop. Besides, the relaxor ferroelectric PMN-PT has been also epitaxially grown on STO/Si and confirmed by XRD and transmission electrical microscopy (TEM). This single crystalline film has the perovskite phase without the appearance of pyrochlore. Moreover, the study of infrared transmission using synchrotron radiation has proven a diffused phase transition over a large range of temperature, indicating a typical relaxor ferroelectric material. The other interesting in the single crystalline PZT films deposited on silicon and SOI is to employ them in the application of MEMS devices, where the standard silicon techniques are used. The microfabrication process performed in the cleanroom has permitted to realize cantilevers and membranes in order to mechanically characterize the piezoelectric layers. Mechanical deflection under the application of an electric voltage could be detected by interferometry. Eventually, this characterization by interferometry has been studied using the modeling based on finite element method and analytic method. In the future, it will be necessary to optimize the microfabrication process of MEMS devices based on single crystalline piezoelectric films in order to ameliorate the electromechanical performance. Finally, the characterizations at MEMS device level must be developed for their utilization in the future applications
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Breuss, Fritz. "WTO dispute settlement from an economic perspective. More failure than success?" Forschungsinstitut für Europafragen, WU Vienna University of Economics and Business, 2001. http://epub.wu.ac.at/1046/1/document.pdf.
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Since its inception in 1995, more than 200 disputes have been raised under the WTO Dispute Settlement Understanding (DSU). In spite of the obvious numerical success of the DS system of the WTO, in practice several shortcomings call for institutional and/or procedural change. This analysis deals with the economic aspects of the DS system. First, it turns out that the WTO DS system seems to be "biased". The larger and richer trading nations (USA, EU) are the main users of this system, either because of the larger involvement in world trade, or because the LDCs simply lack the legal resources. Second, in taking advantage of recent theoretical explanations of the WTO system in general (trade talks) and the DS system in particular (aberrations from WTO compliance can lead to trade wars) one can theoretically derive the relative robust result concerning the present practice of the WTO DS system: retaliation with tariffs is ineffective, distorts allocation and is difficult to control. This is also demonstrated in an CGE model analysis for the most popular disputes between the EU and the USA: the Hormones, the Bananas and the FSC cases. The major conclusion of our economic evaluation is that the DS system of retaliation should be changed towards a transfer-like retaliation system. (author's abstract)Series: EI Working Papers / Europainstitut
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Ramos, Ana V. "Epitaxial Cobalt-Ferrite Thin Films for Room Temperature Spin Filtering." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2008. http://tel.archives-ouvertes.fr/tel-00394398.
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Le filtrage de spin est un phénomène physique qui permet de générer des courants d'électrons polarisés en spin grâce au transport sélectif à travers une barrière tunnel magnétique. Dans cette thèse, nous présentons une étude du matériau ferrite de cobalt (CoFe2O4), dont le caractère isolant et la température de Curie élevée en font un très bon candidat pour le filtrage de spin à température ambiante. L'élaboration des couches minces de CoFe2O4 a été réalisée par épitaxie par jets moléculaires assistée par plasma d'oxygène. Les propriétés structurales, chimiques et magnétiques ont été étudiées par plusieurs méthodes de caractérisation in situ et ex situ. Des jonctions tunnel à base de CoFe2O4 ont été préparées pour des mesures de transport tunnel polarisé en spin, soit par la méthode de Meservey-Tedrow, soit par des mesures de magnétorésistance tunnel (TMR). Dans ce dernier cas, nous avons porté une attention particulière au retournement magnétique de la barrière tunnel de CoFe2O4 et de la contre électrode magnétique (Co ou Fe3O4), une étape cruciale avant toute mesure de TMR. Dans les deux cas, les mesures de transport tunnel polarisé en spin ont révélé des polarisations significatives du courant tunnel à basse température, et à température ambiante pour les mesures de TMR. Par ailleurs, nous avons trouvé une dépendance unique entre la TMR et la tension appliquée qui reproduit celle prédite théoriquement pour les barrières tunnel magnétiques. Nous démontrons ainsi que les barrières tunnel de CoFe2O4 constituent un système modèle pour étudier le filtrage de spin dans une large gamme de températures.
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Alberternst, Stephan, and Caren Sureth-Sloane. "The Effect of Taxes on Corporate Financing Decisions - Evidence from the German Interest Barrier." WU Vienna University of Economics and Business, Universität Wien, 2015. http://epub.wu.ac.at/4884/1/SSRN%2Did2563572.pdf.
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The literature suggests that when taking tax effects into account, debt ought to be preferable
to equity. Thus, with all else being equal, levered firms are expected to show higher firm values.
However, there are no uniform predictions of the size of this tax benefit from interest deductibility
nor on the effect of changes in interest deductibility. We believe that the German corporate tax reform
in 2008, which introduced an interest barrier, can serve as a promising "quasiexperiment" to investigate the effects from a reform of interest deductibility. A study of this reform on the basis of German financial statement data is of general interest because, first, similar interest barriers have been introduced in several countries and proposed by the OECD to fight BEPS. Second, the major
characteristics of the German tax system can be regarded as representative for most European and major Asian countries. Third, single entity financial statements for German companies allows us to capture tax and capital structure details that have not been available in most prior studies. With significance at the 5% level, we find evidence that the companies that are affected by the interest barrier reduce their leverage by 4.7 percentage points more than companies that are not affected by the interest barrier. We are the first to employ a detailed matching approach to the underlying rich dataset, which enables us to overcome several limitations of previous studies. Our results imply that capital structure reactions most likely have been underestimated in previous studies.Series: WU International Taxation Research Paper Series
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Simon, Yolande. "Prospects for the French fighter industry in a post-cold war environment is the future more than a mirage? /." Santa Monica, CA : RAND, 1993. http://www.rand.org/pubs/rgs%5Fdissertations/RGSD106/.
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Gamoran, Jesse. "“I had this dream, this desire, this vision of 35 years – to see it all once more...”The Munich Visiting Program, 1960-1972." Oberlin College Honors Theses / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1483517620887328.
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Widmann, Frédéric. "Epitaxie par jets moléculaires de GaN, AlN, InN et leurs alliages : physique de la croissance et réalisation de nanostructures." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10234.
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Ce travail a porte sur la croissance epitaxiale des nitrures d'elements iii gan, aln, et inn, en utilisant l'epitaxie par jets moleculaires assistee par plasma d'azote. Nous avons optimise les premiers stades de la croissance de gan ou aln sur substrat al#2o#3 (0001). Le processus utilise consiste a nitrurer la surface du substrat a l'aide du plasma d'azote, afin de la transformer en aln, puis a faire croitre une couche tampon d'aln ou de gan a basse temperature, avant de reprendre la croissance de gan ou aln a haute temperature (680 a 750c). Nous avons en particulier etudie les proprietes d'une couche de gan en fonction de la temperature a laquelle est realisee l'etape de nitruration. Lorsque les conditions de demarrage de la croissance sont optimisees, nous avons pu observer des oscillations de rheed pendant la croissance de la couche de gan. Nous avons etudie l'effet du rapport v/iii sur la morphologie de surface et les proprietes optiques et structurales de cette couche. Nous avons propose l'utilisation de l'indium en tant que surfactant pour ameliorer ces proprietes. Nous avons ensuite aborde la realisation de superreseaux gan/aln dont nous avons optimise les interfaces. Les mecanismes de relaxation des contraintes de aln sur gan et gan sur aln ont ete etudies. Nous avons egalement elabore les alliages algan et ingan, comme barrieres quantiques dans les heterostructures. Nous avons montre que la relaxation elastique des contraintes de gan en epitaxie sur aln donne lieu a la formation d'ilots de tailles nanometriques, qui se comportent comme des boites quantiques. Leur densite et leur taille dependent de la temperature de croissance, et des conditions de murissement apres croissance. Les proprietes optiques de ces ilots sont gouvernees a la fois par les effets de confinement quantique et par le fort champ piezo-electrique induit par la contrainte dans les ilots.
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Fontaine, Chantal. "Heteroepitaxie par jets moeculaires : systeme (ca,sr)f::(2) - gaas." Toulouse 3, 1987. http://www.theses.fr/1987TOU30135.
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Dans la premiere partie du memoire sont etudies les mecanismes de formation de defauts pendant la croissance cristalline, les contraintes s'exercant sur les couches heteroepitaxiales, la possibilite de relaxation de ces contraintes par creation de defauts ainsi que les solutions pratiques envisagees pour eliminer ces defauts. Dans la seconde partie sont presentes et analyses les resultats experimentaux obtenus sur les structures (ca,sr)f::(2)/gaas et gaas/(ca,sr)f::(2) realisees par epitaxie par jets moleculaires. Sont consideres les proprietes des interfaces, les relations d'epitaxie, les mecanismes de croissance et les contraintes. Finalement, sont discutees les applications potentielles de ce type de structures et leur compatibilite avec les proprietes optiques et electriques des deux materiaux elabores
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Chaluvadi, Sandeep kumar. "Influence of the epitaxial strain on magnetic anisotropy in LSMO thin films for spintronics applications." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC248/document.
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Nous présentons une étude des effets de contrainte induits par l’épitaxie dans des couches minces La1-xSrxMnO3 (LSMO) (001) (x = 0.33) pour 3 épaisseurs de films (50, 25 et 12 nm) déposés par Ablation Laser Pulsée (PLD) sur différents substrats tels que SrTiO3 (STO) (001), STO buffered MgO (001), NdGaO3 (NGO) (110) et (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) (001). L’étude est complétée par l’effet de la composition sur les propriétés magnétiques de couches minces de La1-xSrxMnO3 avec x=0,33 et 0,38 déposées par Epitaxie à Jets Moléculaires (MBE). Des caractérisations par diffraction de rayons X (XRD), et microscopie à force atomique (AFM), des mesures de résistivité électrique en quatre points en fonction de la température, d’aimantation par magnetometrie à SQUID (Superconducting Quantum Interference Device) et d’anisotropie magnétique par magnétométrie magnéto-optique Kerr vectorielle (MOKE) sont présentées. Les évolutions angulaires de l’anisotropie magnétique, de l’aimantation à rémanence, du champ coercitif et du champ de renversement d’aimantation ont ainsi pu être analysées pour des films épitaxiés LSMO de différentes épaisseurs. Des études en fonction de la température complètent les données. L’origine de l’anisotropie (magnétique, magnétocristalline, magnétostrictive ou liée aux effets de marches et d’angle de désorientation du substrat) est finalement discutéeWe report a quantitative analysis of thickness dependent epitaxial strain-induced effects in La1-xSrxMnO3 (LSMO) (001) (x = 0.33) thin films of thicknesses (50, 25 and 12 nm) grown on various single crystal substrates such as SrTiO3 (STO) (001), STO buffered MgO (001), NdGaO3 (NGO) (110) and (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) (001) by Pulsed Laser Deposition (PLD) technique. We also report the composition dependent magnetic properties of LSMO thin films with x = 0.33 and 0.38 in particular grown onto LSAT (001) substrate by Molecular Beam Epitaxy (MBE). The study mainly includes measurements such as X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), temperature dependent four-probe resistivity, magnetization properties by Superconducting Quantum Interference Device (SQUID), magnetic anisotropy by Magneto-Optical Kerr Magnetometry (MOKE). Our results highlight the detailed study of angular evolution and thickness dependent magnetic anisotropy, remanence, coercivity and switching field in epitaxial LSMO thin films. Temperature-dependent studies are also performed on few selected films. We will also discuss the cause of magnetic anisotropy in LSMO films i.e., magneto-crystalline and magnetostriction anisotropy and the effects of steps or substrate mis-cut induced anisotropy
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Fontaine, Christophe. "Hétéroépitaxie par jets moléculaires de semiconducteurs II-VI." Grenoble 1, 1986. http://www.theses.fr/1986GRE10062.
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Etude de l'heteroepitaxie de cdte, cd::(1-x)zn::(x)te et cd::(x)hg::(1-x)te sur cdznte, insb et gaas (001) et (111) et des differents parametres qui gouvernent la qualite cristalline. Il s'avere que la croissance (001) est meilleure que la croissance (111). L'interet d'une interface graduelle est demontre a fort desaccord de maille. A faible desaccord de mailles les contraintes dans les couches epitaxiques ont ete mesurees. Dans ces conditions experimentales, la relaxatioon des couches est gouvernee par un mecanisme de generation de dislocations et non par l'activation thermique des dislocations presentes. Les modeles existants ne permettent pas de decrire la relaxation dans les couches cdte. Presentation d'un modele qui rend compte des observations
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Gros, Patricia. "Epitaxie métal sur semi-conducteur II-VI : cas des terres rares sur CdTe." Grenoble 1, 1993. http://www.theses.fr/1993GRE10079.
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Cette etude concerne l'epitaxie par jets moleculaires de couches metalliques sur du cdte (001). Nous avons montre que l'europium peut s'epitaxier sur du cdte, moyennant une rotation de 45 de ses axes 100 et 010 autour de l'axe de croissance 001. Nous avons mis en evidence que l'interface eu/cdte n'est pas abrupte: nous observons la formation d'une couche interfaciale (ci(eu)) entre la terre rare et le cdte. Nous avons egalement etudie les couches interfaciales formees par depot de samarium ou de neodyme. L'epaisseur de ces couches interfaciales depend de la temperature du substrat. La croissance de l'europium est bidimensionnelle sur une couche interfaciale a base de neodyme ou de samarium tandis qu'elle est tridimensionnelle sur une couche interfaciale a base d'europium. Nous avons pu realiser d'autre part des multicouches du type cdte/ci/cdte. . . Et des couches metalliques enterrees cdte/eu/ci/cdte. Les differentes heterostructures ont ete caracterisees structuralement par rbs et canalisation, et dans une moindre mesure par microscopie electronique en transmission et diffraction x. Nous avons aussi caracterise electriquement l'heterojonction eu/ci(nd)/cdte (dope indium), mis en evidence le caractere ohmique de la jonction et mesure une resistance specifique de contact de 5. 10##3. Cm#2
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Bassani, Franck. "Dopage indium d'hétérostructures CdTe/CdZnTe en épitaxie par jets moléculaires." Grenoble 1, 1993. http://www.theses.fr/1993GRE10043.
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Ce travail concerne le dopage indium des couches minces de cdte et des heterostructures cdte/cdznte elaborees par la technique d'epitaxie par jets moleculaires selon les orientations (001), (111) et (211). Nous avons mis en evidence l'importance des conditions stchiometriques de surface durant la croissance: un flux excedentaire de cd controle ainsi qu'une temperature d'elaboration basse (220c) sont necessaires. Pour une gamme de concentration d'indium comprise entre 10#1#6 et 10#1#8 cm##3, l'analyse des proprietes electrique et optique des couches minces de cdte(001) uniformement dopees montre une activite electrique proche de l'unite et l'absence de centres profonds. Le dopage planaire des heterostructures cdte/cdznte a ete realise avec succes: l'optimisation des conditions de spectrometrie de masse des ions secondaires permet de deduire que le dopant in est tres bien localise spatialement (<15 a); une etude spectroscopique de la variation de l'energie de localisation de l'exciton sur le donneur en fonction du confinement quantique a ete entreprise. Nous presentons egalement les resultats de dopage selon les orientations (111) et (211). L'utilisation de substrats (111) legerement desorientes et orientes (211) permet de s'affranchir des macles. En particulier, l'orientation (211) permet d'elaborer des couches d'excellente qualite cristalline dont les proprietes electriques et optiques sont voisines de celles des couches de cdte(001). Nous avons mis en evidence l'ecrantage du champ piezoelectrique pour une heterostructure cdte/cdznte(211) a dopage module
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Hauge, Bård. "First for the Jew, then for the Gentile a comparative study of Paul's speeches in Acts 13:16-41 and Acts 17:22-31 /." Online full text .pdf document, available to Fuller patrons only, 1991. http://www.tren.com.
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Tetsi, Emmanuel. "Développement de films minces à base de nanoparticules diélectriques et optimisatisation des conditions de dépôt pour fabriquer des condensateurs de découplage utilisés dans des assemblages à haute densité de modules électroniques." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0113/document.
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Dans le cadre de l’intégration tridimensionnelle (3D) associée à l’utilisation d’un nombre croissant de circuits intégrés (CIs), le besoin en condensateurs de découplage à forte densité de capacité (≥ 1 μF.cm-2), capables d’opérer sur une gamme de fréquences de plus en plus étendue, est crucial afin de limiter les fluctuations de tension d’alimentation au niveau des CIs. Le principal frein au développement de ces condensateurs réside dans l’obtention de couches minces (≤ 100 nm) à partir de matériaux ayant une forte permittivité relative (ε_r > 200 à 1 GHz), des technologies compatibles avec une intégration à grande échelle, et peu coûteux.L’approche proposée dans cette thèse s’appuie d’une part, sur la possibilité de synthétiser des nanoparticules diélectriques à base de Ba0.6Sr0.4TiO3 [BST] (Ø = 16 ± 2 nm, ε_r = 260 à 1 kHz) - obtenues en milieux fluides supercritiques - comme matériau diélectrique et d’autre part, sur la pulvérisation de jets ou spray coating comme technologie de dépôt en couches minces. Dans un premier temps, les nanoparticules de BST ont été synthétisées et fonctionnalisées par l’acide 3-aminopropylphosphonique (APA), dans le but de les disperser dans un solvant et d’obtenir des suspensions colloïdales stables. Les ligands ont aussi pour fonction d’améliorer la tenue mécanique des films (auto-assemblage) sur le substrat de cuivre (Cu). La variation de paramètres liés à la solution à base des nanoparticules (concentration, durée de dispersion mécanique) et à la technique de dépôt (température du substrat, débit), ont permis d’optimiser les conditions pour obtenir des films uniformes à base de nanoparticules fonctionnalisées (BST-APA). Des films de 200 ± 50 nm d’épaisseur ont ainsi pu être obtenus. Après dépôt de plots d’aluminium (Al) sur les films à base de BST-APA et utilisés comme électrode supérieure, les caractéristiques capacité-tension (C-V) et courant-tension (I-V) des condensateurs de structure Al/BST-APA/Cu ont permis d’extraire une densité de capacité élevée (0.71 μF.cm-2) et une densité de courant de fuite (25 μA.cm-2) mesurées à 1 V. Les résultats obtenus au cours de cette thèse montent que la pulvérisation de jets est une alternative aux procédés coûteux reportés (ablation laser, pulvérisation) dans l’état de l’art, pour la fabrication de condensateurs de hautes performances.Mots clés : Condensateurs MIM, couches minces, fluides supercritiques, diélectriques, Ba0.6Sr0.4TiO3, pulvérisation de jets, nanofabricationWithin the three-dimensional (3D) integration associated with the use of an increasing amount of integrated circuits (ICs), there is strong need of high capacitance density (≥ 1 μF.cm-2) decoupling capacitors, able to operate on large frequency bandwidth, in order to reduce the noise that can compromise the signal integrity in ICs. The main challenge of these capacitors relies on the deposition of thin films (≤ 100 nm) using innovative materials with high relative permittivity (ε_r > 200 à 1 GHz) and «low cost» technologies compatible with large scale integration.On one hand, the proposed approach in this thesis benefits from the possibility of synthetizing – by the supercritical fluid technology – and using Ba0.6Sr0.4TiO3 (BST) nanoparticles (Ø = 16 ± 2 nm, ε_r = 260 at1 kHz) as dielectric material and on the other hand, from the use of spray coating as technique for the deposition of these materials as thin films. First of all, the BST nanoparticles synthesized are functionalized with specific ligands (3-aminopropylphosphonic acid, APA), in order to obtain colloidal suspensions composed by aggregates with size (Ø < 100 nm) showing few fluctuations during two months. The other function of ligands is to improve the adhesion of the deposited films (self-assembling) on the copper (Cu) substrate. Different solvent are studied for the preparation of the solutions : N-méthyl-2-pyrrolidone (NMP), water, methanol and ethanol. The variation of different parameters related to the solution and the deposition technique helped us to define the optimal conditions leading to different thickness of film (200 – 1000 nm) based on pristine (BST) and functionalized nanoparticles (BST-APA). Using ethanol instead of NMP as solvent, enabled us to prevent de formation of a copper oxide layer and organic residues. After deposition of aluminum pads (Al) on BST or BST-APA films and used as top electrode, the capacitance-voltage (C-V) and current-voltage (I-V) characteristics of capacitors with metal-insulator-metal (MIM) structure enabled us to achieve high capacitance density (~ 0.7 μF.cm-2) and low leakage current (~ 25 μA.cm-2) at 1 V.Keywords: MIM capacitors, thin films, supercritical fluids, Ba0.6Sr0.4TiO3, spray coating, nanofabrication in cleanroom
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Guille, Claire. "Etude de la formation par epitaxie par jets moleculaires des interfaces entre inas et gaas." Paris 6, 1987. http://www.theses.fr/1987PA066415.
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Malgre le fort desaccord parametrique existant entre gaas et inas (7,2%), il est possible de realiser des couches pseudomorphes de l'un des materiaux sur l'autre, en se limitant a des couches d'epaisseurs inferieures a une dizaine d'a. Dans ces conditions,l'interface inas/gaas est plane et chimiquement abrupte, a la demi-couche pres. L'interface inverse est diffuse et rugueuse a l'echelle atomique. Au cours de la formulation de cette heterojonction, il y a segregation d'in en surface et formation d'un compose ternaire. Ce type de phenomene de segregation d'in se produit egalement dans les composes ternaires ingaas et peut etre a l'origine de leur rugosite superficielle. Etude comparative avec d'autres systemes iii-as
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Plšek, Radek. "Měření vlastností tenkých vrstev metodami zobrazovací reflektometrie a Kerrova jevu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-227912.
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This thesis is divided into three main sections that deal with optical and magnetic thin films properties and their measurements techniques. Principles of the spectroscopic reflectometry and measurements of optical properties are described in the first part. Results of imaging reflectometry are most important. This technique is based on in situ monitoring of optical properties of SiO2 thin films during etching over the area cca 10 × 13 mm2. In next section magnetic properties of thin films and new apparatus built on the Institute of Physical Engineering of BUT are shown. Magnetic properties were observed by longitudinal magneto-optical Kerr effect. The construction of the device is based on a light beam with rectilinear polarization reflected from magnetic material with turned polarization. For investigation of local magnetic properties of microstructures a microscope objective focusing laser beam on the sample is used. The last part of the thesis is aimed on improving of a spin valve structure Co/Cu/NiFe. This work was done within the frame of the Erasmus project in Laboratoire Louis Néel in Grenoble. The goal was to achieve the value of GMR (Giant Magnetoresistance) as high as possible by changing of deposition parameters. This value describes the rate of resistances in different mutual directions of magnetization in trilayers.
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Turco, Françoise. "Applications de techniques d'analyse in situ à l'épitaxie par jets moléculaires du système (Al, Ga, In) As." Grenoble INPG, 1988. http://www.theses.fr/1988INPG0016.
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L'etude des oscillations d'intensite de diffraction rheed en incidence rasante dursant la croissance de (al,ga,in)as conduit a un controle en temps reel en fonction des parametres (temperature, composition de la phase solide, pressions incidentes). Le couplage in situ avec la spectroscopie xps a permis de mettre en evidence, au cours de la croissance de algaas, gainas et alinas, la segregation en surface de l'element iii le moins lie a as. Par la technique des oscillations de rheed, determination des variations du coefficient d'incorporation de in dans alinas en fonction de la contrainte de la couche par le support, de la vitesse de croissance et de la pression de as. Le modele thermodynamique permet de rendre compte de ces variations
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Arlery, Magali. "Etude par microscopie électronique à transmission de couches et structures semi-conductrices GaN/AlxGa(1-x)N." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10047.
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Nous presentons une etude structurale de depots epais de gan sur alumine et d'heterostructures gan / al#xga#1#-#xn de basse dimensionnalite. Les systemes etudies ont ete elabores par epitaxie par jet moleculaire (mbe) ou par depot en phase vapeur d'organo-metalliques (mocvd). La technique d'investigation est la microscopie electronique a transmission, utilisee en modes conventionnel, haute resolution et faisceau convergent. La premiere partie de l'etude traite de la croissance optimisee de couches de gan sur substrat d'alumine. La polarite des depots est le parametre clef de cette croissance. En effet, la presence de domaines d'inversion de polarite ga dans une matrice a polarite n provoque une croissance sous forme d'ilots hexagonaux, tandis qu'une matrice a polarite ga assure une surface de croissance lisse. Les depots realises contiennent tous des dislocations en grande densite (10#+#1#0/cm#2), dont les vecteurs de burgers sont egaux a 1/3 <2,1,1,0>, 1/3 <2,1,1,3> et 0001. Des nanotubes sont formes par l'ouverture locale du coeur de dislocations 0001. Des defauts prismatiques 2,1,1,0 et 0,1,1,0 ont aussi ete observes. Les derniers forment les parois des domaines d'inversion de polarite et introduisent une translation de 1/20001 entre les cristaux de polarites opposees. Dans une seconde partie, differentes heterostructures gan / al#xga#1#-#xn (puits, super-reseaux et boites quantiques) sont etudiees a l'echelle atomique par analyse quantitative des images haute resolution. L'epitaxie de gan sur al#. #1#5ga#. #8#5n reste coherente pour 16 monocouches deposees. Par contre, une relaxation partielle apparait dans un super-reseau gan / aln dont les couches ont une epaisseur superieure a 11 monocouches. Les heterostructures aln / gan sont caracterisees par une faible miscibilite et des interfaces relativement abruptes. Selon la temperature, les couches de gan deposees sur aln adoptent un mode de croissance bidimensionnel ou de type stranski-krastanov. Ce dernier mode de croissance permet le confinement d'ilots de gan dans aln et ouvre la voie a la realisation de boites quantiques.
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Hnízdil, Milan. "Vývoj metod in-line tepelného zpracování." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-234019.
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In-line heat treatment is a part of technological process uses a phase and structure changes to obtain required mechanical properties. Heat treatment of rolled products offers a reduction of steel making costs and a creation of new steel products. For example the TRIP steel is a part of modern steels which is used in the automobile industry for higher safety of passengers. The heat treatment is often described in the literature. But the authors are often focused on the method how to get the required structure and mechanical properties for different metallic materials. Nevertheless just few articles are focused on the technical observing of temperature regimes and which parameter is necessary to consider during designing the cooling section. Eight parameters were tested by the experimental way to examine their influence on the cooling intensity. They were: gravity (orientation of the cooled surface), coolant pressure, amount of coolant spraying on the surface (the flow rate), rolling velocity, nozzle configuration, kind of nozzles (full cone or flat fan nozzle), coolant temperature and the surface quality (surface roughness and scales). All these parameters have an influence the heat transfer coefficient. Based on knowledge gained in this work was created the cooling section, which comply with the required cooling temperature regimes.
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Ho, King Tong. "The poetics of making a new cross-cultural aesthetics of art making in digital art through the creative integration of Western digital ink jet printmaking technology with Chinese traditional art substrates : this exegesis is submitted to AUT University in partial fulfillment of the degree of Doctor of Philosophy." Click here to access this resource online, 2007. http://hdl.handle.net/10292/333.
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Soulisse, Pierre. "Développement d'un dispositif expérimental pour la diffraction d'atomes rapides et étude de surfaces d'isolants ioniques." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00625450.
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Ce mémoire de thèse présente le développement d'un dispositif expérimental spécialement conçu pour l'étude de la diffraction d'atomes rapides et son utilisation pour suivre la croissance de couches minces sur un bâti d'épitaxie. Des études de surfaces de KBr(100) et de NaCl(100) avec ce nouveau dispositif sont présentées. Nous nous sommes intéressés notamment à la forme du potentiel que les atomes perçoivent lorsqu'ils diffusent sur une surface de KBr(100). Nous avons également mis en évidence lors de ces études un nouveau régime de diffraction qui semble correspondre à des mouvements longitudinaux et normaux cohérents. Grâce à des images mieux résolues, nous avons montré comment la diffraction d'atomes rapides permet d'observer et quantifier des défauts topologiques comme la mosaïcité. Une étude d'une surface d'Argent (110) est aussi présentée. Elle a permis d'observer la diffraction d'atomes rapides sur les métaux, montrant ainsi que GIFAD est applicable aux trois types de matériaux (isolants, semi-conducteurs et métaux) et que les processus d'excitations électroniques sur ces surfaces ne détruisent pas complètement la cohérence. Enfin des premiers résultats de GIFAD en tant que technique de suivi de croissance par épitaxie sont présentés dans ce travail.
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Kvítek, Adam. "Tvorba metodiky plánování procesního řízení výroby." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2018. http://www.nusl.cz/ntk/nusl-377625.
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Hýl, Petr. "Slovinské národní divadlo v Lublani." Master's thesis, Vysoké učení technické v Brně. Fakulta architektury, 2009. http://www.nusl.cz/ntk/nusl-215582.
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Singhal, Shrawan. "Jet and coat of adaptive sustainable thin films." 2012. http://hdl.handle.net/2152/22157.
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Deposition of nanoscale thickness films is ubiquitous in micro- and nano-scale device manufacturing. Current techniques such as spin-coating and chemical vapor deposition are designed to create only uniform thin films, and can be wasteful in material consumption. They lack the ability to adaptively prescribe desired film thickness profiles. This dissertation presents a novel inkjet-based zero-waste polymer deposition process referred to as Jet and Coat of Adaptive Sustainable Thin Films or J-CAST. The core of this process is built on an experimentally validated multi-scale fluid evolution model, based on extensions of lubrication theory. This model involves a nano-scale fluid film sandwiched between two flat plates: a compliant superstrate and a rigid substrate, with spatial topography on both surfaces. Accounting for the flexural elasticity of the compliant superstrate, and describing the temporal evolution of the fluid film in the presence of different boundary conditions reveals that instead of seeking process equilibrium, non-equilibrium transients should be exploited to guide film deposition. This forms the first core concept behind the process. This concept also enables robust full-wafer processes for creation of uniform films as well as nanoscale films with prescribed variation of thickness at mm-scale spatial wavelengths. The use of inkjets enables zero-waste adaptive material deposition with the preferred drop volumes and locations obtained from an inverse optimization formulation. This forms the second core concept behind the process. The optimization is based on the prescribed film thickness profile and typically involves >100,000 integer parameters. Using simplifying approximations for the same, three specific applications have been discussed - gradient surfaces in combinatorial materials science and research, elliptical profiles with ~10km radius of curvature for X-ray nanoscopy applications and polishing of starting wafer surfaces for mitigation of existing nanotopography. In addition, the potential of extending the demonstrated process to high throughput roll-roll systems has also been mentioned by modifying the model to incorporate the compliance of the substrate along with that of the superstrate.text
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SU, YU-KAI, and 蘇郁凱. "Nickel oxide thin films deposited by dielectric barrier discharge plasma jet." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/629h4s.
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碩士國立高雄應用科技大學
化學工程與材料工程系博碩士班
106
In this study, nickel oxide (NiO) thin films were deposited on glass substrate at temperature of 250℃and 300℃ by a homemade low temperature atmospheic pressure plasma system. The axial gas flow rate of 50 sccm to 200 sccm are used in this study. No diffraction peak was observed at 250℃ by the x-ray diffraction analysis. Nither the formation of particles nor thin films could not be found on the surface by a FE-SEM, which might be due to the insufficient thermal energy of the substrate. When the substrate temperature was 300℃ and the axial flow rate of 50 sccm, the NiO thin films were not formed. However, the NiO thin films were formed at the axial flow rate of 100 sccm to 200 sccm, which is confirmed by x-ray diffraction patterns (JCPDS #47-1049). The transmittance of the NiO thin films was 48% (100 sccm), 38% (150 sccm) and 35% (200 sccm) in the visible region. The best condition for the formation of the NiO thin films was the axial flow rate of 100 sccm at 300℃. The NiO thin films had P-type characteristics by a hot-probe method. The resistivity, electrical conductivity, carrier concentration, and mobility of the NiO thin films are measured by a Hall effect.
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Hsu, Chun-Ming, and 許峻銘. "Characterization of Oxide Thin Films Deposited by an Atmospheric Pressure Plasma Jet." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/35837955388715490041.
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碩士國立臺灣大學
化學工程學研究所
102
Deposition zinc oxide and silica-like thin films by the atmospheric pressure plasma jet were studied. To understand the plasma system property and application fields, we first investigate into the plasma optical emission spectra and gas temperature by changing the manipulate variable such as applied voltage, gas type and flowrate. Our research has demonstrated that higher applied voltage and lower gas flowrate will decrease the plasma gas temperature because of the different energy density. But the higher flowrate cause the plasma gas have more excited molecules. By the simulation of the plasma downstream intensity distribution, temperature trend and NO concentration, we found that the turbulence type matchs the downstream flowfield well and it illustrates the non-negligible of outside ambient gas. Futher, our study shows the plasma gas temperature and substrate temperature by the method of simulation molecules emission and thermalcouple measurement. The downstream gas temperature are between 950 K to 1200 K, which makes the plasma system belonging to high temperature plasma type. To deposit zinc oxide thin films, we use the 1.7 MHz nebulizer and nitrogen carrier gas to spray the precursor solution into the plasma system. The different precursor effect, applied voltage and gas flowrate effect were studied in this research. First, we found the only one precursor, zinc chloride, can deposit the less roughness, smooth and high crystalline thin films. Otherwise the particle-like structure appears. Next, to find the optimized condition of zinc chloride as precursor deposits zinc oxide thin films, the gas flowrate and applied voltage were setting as manipulate variable. In our study, we found that under the applied voltage 275 V and gas flow rate 30 slm, the deposition has best film property with resistivity of 1.4 ohm-cm and transimmion near 90 %. Otherwise the deposition will appear the sheet-like structure and has poor optical and electric property. By the XRD identified, we found the sheet-like structure is the ZHC (Zn5(OH)8Cl2‧H2O), which is the intermedia of the reaction. The appearance of ZHC can be explained by the non-enough power and shorter residence times in those condition. In next research topic, the silica-like thin films deposited by the APPJ were studied. In this system, we use the bubbler method with nitrogen as the carrier gas to send the saturated vapor pressure to the plasma system. Three different precursors were tested, which are tetraethylorthosilicate (TEOS), Hexamethyldisiloxane (HMDSO) and hexamethyldisilazane (HMDSN). Each precursor has their optimized deposited condition and all deposition show the inorganic-like silica structure. In the TEOS system, we found the deposition rate was much lower than the others but the film has the advantage of smoothness and well-coverage. In the HMDSN system, the deposition rate were rapid but the films have worst leakage current density. It is in regard to its complicated bonding and structure. On the contrary, the HMDSO system has advantage of higher deposition rate, less-roughness and lower leakage current. In this research, we use films deposited from HMDSO as the dielectric layer in the thin films transistor (TFT) and it can work quite well. This TFT result shows the potential and capable of this atmospheric pressure deposited films as the device’s dielectric layer.
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Chiang, Kai-Chieh, and 姜愷傑. "In‐process Monitoring of Atmospheric Pressure Pulsed Plasma Jet on Thin Film Deposition." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/09717359323822858295.
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碩士國立臺灣大學
機械工程學研究所
105
This study is focused on atmospheric pressure plasma jet (APPJ) system which is driven by direct current pulses and deposits thin film of zinc oxide doped with gallium. This system, however, is different from low pressure plasma‐enhanced chemical vapor deposition (PECVD). This works under atmospheric environment; therefore, cost of vacuum pump system is avoided. With the grid‐shaped path, this system is covered varying size of thin film area. This study aims on in‐time monitoring of the process. Plasma density is estimated by analyzing the voltage and current signals into nozzle head. Plasma status is also determined by plasma afterglow with temperature and outlet length. Plasma density and afterglow are used to evaluate the quality of thin films. Moreover, phase angles between voltage and current is observed to be a reference to the processing quality. With all the data combined, it is able to establish in‐time process monitoring. Plasma diagnose by input main gas, voltage and pulses is focused in this thesis. While lower the main gas flow rate, the estimated plasma density is higher and same to the afterglow length and temperature. On the other hand, phase angle is lower and thus the sheet resistant is lower. As for the input pulses, while pulse‐on time, Ton, is longer, the estimated plasma density is higher, as well as the afterglow length and temperature is higher. Therefore, the sheet resistant is lower. However, the pulse frequency is not related to the estimated plasma density, which is analyzed by electrical signals during Ton while frequency is associated with Toff, the pulse‐off time. Despite this, as the input frequency increasing, the phase angle decreases. The lowest sheet resistance is observed while the phase angle is under 1°. The input voltage is found to be related with the input frequency in this study, as that the pulse frequency for lowest sheet resistant varies with the different input voltage. While the input voltage is 160, 180 or 200V, as the different frequency input, the phase angles and sheet resistances are in the same trend. The lowest resistances of thin films are all found under the lowest phase angle of electrical signals, the hottest afterglow and the longest length of afterglow. The frequency at this moment is seen to be the best for the process. At the experiment of pins, the lowest sheet resistance is found when pins are out of the nozzle. Nevertheless, the gas flow rate is high when without pins, thus, the estimated plasma density is low. At the end of the study, the steady of process is examined with large area deposition. The estimated plasma density varies within 7% and the result of sheet resistance meets the manufacturing standard.
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Wang, Sha-Man, and 王紗曼. "The Process Investigation of Polymer Thin Film Transistor by Ink-Jet Printing Technology." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/13112786108443865484.
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碩士元智大學
光電工程研究所
94
The organic semiconductor used as the active layer of thin film transistor have widely been widely studied in recent years. Since the organic film of organic thin film transistor (OTFT) is fabricated on the dielectric layer, the performance of OTFT strongly depends on the semiconductor/dielectric interface due to the physical and chanical interactions between the organic layer and the dielectric layer. In this paper, Poly（3-hexylthiophene）（P3HT）was used as an active layer of OTFT and the dielectric surface of SiO2 gate were treated by the process of normal wet-cleaning、O2-plasma、hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (OTS). The purpose of this work is to show that the performance canbe improved with different treatments of dielectric/polymer interface. By using the advantages of polymer dissolved in the organic solvent, the polymer solution can be ink-jet printed with ink-jet technique to fabricate the semiconductor layer of OTFT and to reach the purpose of low-cost and mass-production. By using direct ink-jet printing of solution process, it can provide a new route to fabricate OTFT devices. The experimental result show that the surface treatment of SiO2 with OTS can be allowed to enhance the mobility of the carrier. The surface potential changed by using self-assembled monolayer like OTS technique can lead to hydrophobic state so that the mobility is improved. The highest mobility obtained from OTS-treated sample is nearly 2.026×10-2cm2/Vs. The semiconductor layer of thin film transistor fabricated by ink-jet printing polymer solution process has already been succeeded in this laboratory at present. The measurent of mobility obtained from ink-jet printed sample can achieve 3.892×10-3cm2/Vs. However, it is unsatisfactory compared with spin-coating devices. If there experimented in ink-jet printing process can further be modified, the device performances by also be promted.
49
Wu, Ming-Yu, and 吳明裕. "Cutting Analysis of Thin Brittle Plate by High-Pressure Mini-Slurry Suspension Jet." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/92913918812523920929.
Full textAbstract:
碩士國立清華大學
動力機械工程學系
88
The current study analyzes the properties of glass and silicon kerf under Abrasive Suspension Jet (ASJ) cutting. The system consists of a high-pressure cylinder and piston. The highly pressurized water from the pump pushes the isolator downward while the premixed slurry is pumped through the orifice. The system is operated under 105 MPa with a 0.1-mm diameter orifice. The relations between the abrasive volume concentration, pressure, traverse speed, abrasive size, the kerf width at upper, bottom and affected zones, kerf ratio, kerf taper, roughness, and the maximum traverse speed were studied. Scanning Electron Microscope (SEM) and optical microscope were used to observe the surface waviness of kerf, plastic flow and trace of abrasives under impact. The experiment results show that the maximum traverse speed occurs at the pressure of 105 MPa, 5% volume concentration, and 1500 mesh SiC abrasive, while the minimum roughness occurs at the pressure of 70 MPa and 2000 mesh SiC abrasive.
50
Lin, Wei-Hsiang, and 林暐翔. "Fabrication and Performance Improvement on All Ink-Jet Printed Flexible Organic Thin Film Transistor." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/83293950040239026060.
Full textAbstract:
碩士臺灣大學
工程科學及海洋工程學研究所
95
With the advancement of the organic electronic material, many flexible electronics applications appear. Within all these applications, OLED, LCD, e-paper, RFID-tag, sensor , solar cell, etc. are some of the most well-known examples. In addition to develop new materials, associated solution process were also investi閘極d seriously with an attempt to improve manufacturing efficiency as well. To satisfly the low temperature processing requirements for plastic substrate, the ink-jet printing has become one of best candidate for developing the next-generation fabrication process for flexible electronics due to its high degree of freedom, high accurate, low cost, etc. In this thesis, the printhead made by MicroFab Technologies, Inc. was integrated with the newly developed pneumatics controller system, piezoelectric driver system, ink-jet observing system, substrate positioning system and software to achieve stable fabricating process with highly yield and highly repeatable. Moreover, this newly developed system can minimize the device and perform accurate fabrication requirements such as controllable channel length, film thickness, etc. OTFT and silver conducting lines were successfully fabricated in this thesis. The fabrication process used PI tape as the substrate, PEDOT/PSS doping EG as the conducting material, PVP blend PMF as the dielectric layer, P3HT or pentacne precursor as the active layer, to arrive at an all ink-jet, all organic OTFT, To further improve the electric performance techniques such as new package, reducing thickness of active layer, surface treatment, and investigate the influence of channel length and dielectric layer thickness, etc. were all integrated in order to obtain the best OTFT circuitry performance.