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Lins, Leila Cristina Rosa de. "Propagação da lichieira por alporquia em diferentes substratos e épocas do ano." Universidade Federal de Viçosa, 2013. http://locus.ufv.br/handle/123456789/4593.
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The aim of this study was to assess the influence of different times of the year and substrates on the rooting of air layers of lychee (Litchi chinensis Sonn.) for the production of seedlings to ensure the formation of uniform and productive orchards. Air layers were done in plants of the Bengal cultivar using leafy and healthy woody branches, with about 1.0 to 1.5 cm in diameter, in which complete girdling were performed with 2.0 cm wide at a distance of 30 to 40 cm below the apex. Then the branches were wrapped in moistened substrate. Air layering was made at six times of the year (January, March, May, July, September and November) and two substrates were used (coconut fiber and sphagnum) in a 6 x 2 factorial design in a randomized block with ten replicates, each block represented by a matrix plant. After 90 days, layers were separated from the matrix plant and evaluated for rooting and callus formation; root number, considering only the primary roots; length, area, volume and diameter of the roots; dry mass of roots and calluses, in addition to the dry mass of shoots (leaves and stems). The months of January, March, September and November showed the best results for allanalyzed variables related to rooting. With respect to the substrates, the only difference was in the months of January and March regarding root number and dry mass of roots, where the sphagnum showed the best results. The month of July was more favorable to the formation of calluses. The period between September and March was more suitable to the propagation of lychee, when there were rooting percentages above 90%, in addition to the formation of large amounts of roots.
Neste estudo, objetivou-se verificar a influência da época do ano e de diferentes substratos no enraizamento de alporques de lichieira (Litchi chinensis Sonn.), visando à produção de mudas que assegurem a formação de pomares uniformes e produtivos. Foram feitos alporques em plantas da cultivar Bengal, utilizando ramos lenhosos bem enfolhados e sadios, com cerca de 1,0 a 1,5 cm de diâmetro, nos quais foram realizados anelamentos completos de 2,0 cm de largura, à distância de 30 a 40 cm abaixo do seu ápice. Em seguida, os ramos foram envoltos por substrato umedecido. Foram avaliadas seis épocas de realização dos alporques (janeiro, março, maio, julho, setembro e novembro) e dois substratos (esfagno e fibra de coco), em um esquema fatorial 6 x 2, no delineamento em blocos casualizados com dez repetições, sendo cada bloco representado por uma planta-matriz. Passados 90 dias, os alporques foram separados da planta-matriz e avaliados quanto à porcentagem de enraizamento e de calejamento; ao número de raízes, considerando apenas as raízes primárias; ao comprimento, à área, ao volume e ao diâmetro das raízes; à massa seca de raízes e calos, além da massa seca da parte aérea (folhas e caule). Os melhores resultados para todas as variáveis relacionadas ao enraizamento analisadas foram verificados nos meses de janeiro, março, setembro e novembro. Com relação aos substratos, houve diferença apenas nos meses de janeiro e março para número de raízes e massa seca de raízes, tendo o esfagno apresentado os melhores resultados. O mês de julho foi mais propício à formação de calos. O período compreendido entre os meses de setembro e março foi o mais propício à propagação da lichieira, quando foram obtidas porcentagens de enraizamento superiores a 90%, além da formação de grande quantidade de raízes.
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Jeyaranjan, Aadithya. "Adhesion of Germanium Electrode on Nickel Substrate for Lithium Ion Battery Applications." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5509.
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Lithium ion batteries (LIBs) have gained increasing popularity due to their high potential, low self-discharge, zero priming and minimal memory effect. However, the emergence of electrical vehicles and hybrid electrical vehicles in the automobile industry, where LIBs are predominantly in use, instilled a need to improve LIB batteries by experimenting with new materials. Graphite, the commonly used anode material for LIBs suffers from low theoretical capacity (372 mA h g-1) and torpid rate performance. Germanium (Ge) seems to be a promising substitute of carbon due to its high theoretical capacity, high Li+ diffusivity and electrical conductivity. However, Ge undergoes large volumetric change (±370%). This causes deboning of the thin film Ge electrode from the substrate current collector, causing a rapid decrease in the electrolytic performance. The process of ion beam mixing claims to have overcome this problem. In our current study, the adhesion strength of Ge thin film over Nickel (Ni) substrate (with and without ion beam mixing) is being measured using nanoindentation and the superlayer indentation test. Nanoindentation is one of the popular techniques to measure the mechanical properties and adhesion of thin film coatings. In this technique, a very small indenter of a desired geometry indents the film/substrate pair and the work of adhesion is calculated by knowing the plastic depth of indentation and the radius of indentation. Superlayer indentation is analogous to normal indentation but with a highly stressed superlayer on top to restrict the out-of-plane displacements, it reduces the plastic pile up around the indenter tip. The results from our study strongly suggest the possibility of dramatically increasing the adhesion strength by ion bombardment, which can be achieved by atomic level intermixing of the film/substrate pair. These, in turn, suggest that Ge could be an effective successor to graphite in the near future.
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Eustache, Etienne. "Microsystèmes de stockage d'énergie sur substrat 3D." Nantes, 2016. https://archive.bu.univ-nantes.fr/pollux/show/show?id=1e832b83-4efd-4a39-8aaf-10735e08b591.
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Conférer de l'autonomie énergétique à des objets électroniques miniatures est un défi. De nouvelles voies de recherche doivent être investiguées pour augmenter les performances des microbatteries (MB) Li-ion et des micro-supercondensateurs (MSC). A ce titre, développer des microsystèmes de stockage en topologie 30 semble être une approche prometteuse pour outrepasser les densités d'énergie des dispositifs planaires. Dans le cadre de cette thèse exploratoire, nous avons réalisé des structures 30 à l'échelle micrométrique en utilisant un procédé de gravure profonde d'un substrat de silicium. Cette architecture est utilisée comme socle commun pour la fabrication de MB Li-ion 30 et de MSC 30. Une électrode négative de MB de TiO2 a été réalisée par dépôt par couche atomique (ALD) sur les structures 30 proposées. Les caractérisations électrochimiques montrent que l'augmentation de la capacité (x30) est proportionnelle à la surface développée par l'architecture 30. Un film conforme de phosphate de lithium (Li3P04) a également été développé par ALD. La conductivité ionique de (=4. 10-7 S/cm) et l'épaisseur limitée (60 nm) de la couche placent ce matériau comme électrolyte solide potentiel de MB 30. Des MSC à électrodes 30 interdigitées ont par ailleurs été fabriqués. Des électrodes de Mn02 ont été déposées en couche mince par dépôt électrolytique sur le substrat 30. Les résultats montrent que cette approche permet d'obtenir des dispositifs pseudocapacitifs à capacités spécifiques particulièrement élevéesProviding autonomy to miniaturized electronic devices is a challenge. New research directions should be investigated in order to increase the performance of Liion microbatteries (MB) and micro-supercapacitors (MSC). Developing power sources with a 30 topology instead is a promising approach to surpass the planar devices energy density. Ln this exploratory thesis, we realized 30 structures at the micrometric scale by deep etching of a silicon substrate. This architecture is used as a common base to fabricate Li-ion MB and MSC. A TiO2 MB negative electrode has been realized by atomic layer deposition (ALD) on top of the microstructures. Electrochemical characterizations show a proportional increase (x30) of the capacity with the specific surface area of the 30 architecture. A conformal lithium phosphate (Li3P04) film has also been developed by ALD. The ionic conductivity (=4. 10-7 S/cm) and the limited thickness (60 nm) of the layer establish this material as a 30 MB potential solid-state electrolyte. Furthermore, MSC with interdigitated 30 electrodes have been fabricated. Mn02 thin films have been deposited by electrodeposition on top of the 30 substrate. Results demonstrate that this approach allow to achieve pseudocapacitive devices with high specific capacitance
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Gil, Rashapal Ram. "Aluminium and its alloy as substrates for the lithium rechargeable electrode." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363538.
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van, Lierop Jean. "Influence of variations in ceramic thickness and bonding substrate on the fracture resistance of lithium disilicate restorations." University of the Western Cape, 2017. http://hdl.handle.net/11394/6626.
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Magister Scientiae Dentium - MSc(Dent)Restorative dentistry aims to replace lost or damaged tooth structure with durable and life-like alternatives. To accommodate the inherent limitations and weakness of the restorative materials, preparation techniques often require the sacrifice of healthy tooth structure to create enough restorative space. This can lead to weakening of the remaining tooth structure, with subsequent damage or catastrophic failure. When using indirect restoratives, the development of adhesive luting agents (adhesive cements) and stronger allporcelain restorations (lithium disilicate) has contributed to the development of “minimally invasive” preparation techniques and concepts such as cavity design optimization (CDO) and bio-substitution. With these techniques, resin materials are combined with ceramic restoratives in an attempt to not only produce strong restorations, but also increase the longevity of the remaining tooth. The clinician needs to therefore find the ideal preparation design that combine such materials to produces a clinically performing restoration while increasing the strength and longevity of the underlying tooth.
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Henrot, Fabien. "Composants à hauts facteurs de forme pour les résonateurs acousto-électriques et les dispositifs électro-optiques sur substrats mono-cristallins." Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2032/document.
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La miniaturisation est l’objectif actuel de tous les fabricants de composants radio-fréquence depuis plusieursdécennies. Si les composants actifs pour la microélectronique sont fondés sur la structuration de plaquesde silicium, les composants passifs reposent sur l’utilisation de cristaux tels que le quartz ou le niobate delithium. Ce dernier est particulièrement utilisé quand il s’agit de générer et exploiter des ondes élastiques, ainsique pour le guidage de faisceaux lumineux afin de réaliser des filtres ou des capteurs sensibles à différentsparamètres environnementaux. L’amélioration du guidage de ces ondes permet un gain en consommation et encompacité des dispositifs mais nécessite une structuration de la matière souvent tridimensionnelle. Cette étapetechnologique clé est industriellement mature pour la mise en forme du silicium, mais s’avère di_cilementtransposable à des matériaux tels que le quartz ou le niobate de lithium. Les travaux présentés dans cemanuscrit visent à réaliser des structures tridimensionnelles à hauts facteurs de forme dans des matériauxmonocristallins à l’aide d’une scie circulaire de précision. Des structures utilisant l’inversion périodique dedomaine ferroélectrique seront réalisées afin de les utiliser pour y guider des ondes élastiques possédant descouplages électromécaniques particulièrement élevées. Le guidage d’ondes optiques par le biais de ces mêmesstructures permet une amélioration du confinement par rapport aux systèmes de guidage massifs classiquescouramment utilisés pour la réalisation de filtre ou de modulateur électro-optiques. En utilisant conjointementle guidage d’ondes optiques et les domaines ferroélectriques alternés, les structures ainsi découpées permettentl’apparition de phénomènes optiques non-linéaires exaltés par l’amélioration du confinement. Ces structuresont ainsi montré leur intérêt dans plusieurs domaines de la physique avec un champ applicatif particulièrementvasteOver the past decades, minutiarization and compacity have become a focus subject for companies specialisedin the manufacturing of radio-frequency components. Active components are typically manuafctured onsilicon wafers with well-known structuring methods. Passive ones are often manufactured on single cristalsuch as Quartz or Lithium Niobate, especially for acoustic wave generation or lightwave guiding. Theguiding of optical or acoustical waves leads to the manufacturing of sensors or filters which can be usedfor telecommunications or for the industry. Improvement in waveguiding allows for less power-consuming andmore compact devices but a 3D-structuring is usually required. This technology readness is high leveled forsilicon structuring but not for single crystals such as Lithium Niobate. This work presents the development andthe manufacturing of high aspect ratio three-dimensionnal structures in single-crystals using precise sawing.These structures show an optical waveguiding capability which allow the improvements of electro-opticmodulators or filters. Combined with a periodic reversing of Lithium Niobate polarization, these structuresallows for bulk acoustic wave generation leading to high electromechanical coupling and equivalent phasevelocity resonant modes. In non-linear optic field, this kind of structures lead to the improvement of secondharmonic generation e_ciency by reducing the cross section of waveguide. The manufactured devices in theframework of this project can actuelly be used in several domains of physic
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Palanisamy, Asha. "High Energy Density Battery for Wearable Electronics and Sensors." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1480511507315736.
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Brigouleix, Catherine. "Elaboration et étude de couches minces électrochromes déposées par pulvérisation cathodique : mise en œuvre de démonstrateurs sur substrat flexible." Bordeaux 1, 2003. http://www.theses.fr/2003BOR12648.
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L'objectif de la thèse est d'étudier des dispositifs électrochromes sur support flexible. Ces systèmes ont une transmission dans le visible et le proche infra-rouge qui peut être modulée sous l'effet d'une tension électrique. Ils sont constitués d'un empilement de couches minces : - un film électrochrome à coloration cathodique à base de WO3, - une couche conductrice ionique au lithium, inorganique (LiPON) ou organique gélifiée, - une contre-électrode à coloration anodique (''LixNi0. 5O'') ou optiquement passive (V2O5). Cet ensemble, compris entre deux électrodes conductrices transparentes est déposé sur PET. Les couches électrochromes et l'électrolyte inorganique sont déposés par pulvérisation cathodique. La corrélation entre paramètres de dépôt, propriétés électrochromes et propriétés structurales a été établieThe aim of this thesis was to study flexible electrochromic devices. They can modulate their visible and near infra-red transmittance under polarization. They are constituted of a stack of thin layers : i. ) an electrochromic active layer based on nanocrystaline WO3, coloured under cathodic bias, ii. ) a lithium-ion conducting electrolyte which can be based either on photopolymerizable organic constituents, or on an inorganic film (LiPON), iii. ) an ion storage counter electrode, which can be either an anodic colouring material such as nanocrystalline ''LixNi0. 5O'', or an optically passive oxide such as nanocristalline lamellar ''V2O5/TiO2''. This set of layers is sandwiched between two transparent conductive electrodes deposited on polyethyleneterephtalate flexible substrates. Electrochromic layers and inorganic electrolyte were deposited by cathodic sputtering. Correlation between deposition parameters, electrochromic properties and structural properties were established
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Kang, Sangbeom. "The epitaxial growth of GaN and A1GaN/GaN Heterostructure Field Effect Transistors (HFET) on Lithium Gallate (LiGaO₂) substrates." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/13903.
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Ravi, Ajaay. "Run-Time Active Leakage Control Mechanism based on a Light Threshold Voltage Hopping Technique (LITHE)." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1302550444.
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Ganiek, Maximilian [Verfasser], and Paul [Akademischer Betreuer] Knochel. "Metalation and Halogen-Lithium exchange of sensitive substrates and mild ester homologation in continuous flow / Maximilian Ganiek ; Betreuer: Paul Knochel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1172634327/34.
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Bohne, Laura [Verfasser], Wolfram [Akademischer Betreuer] Jaegermann, and Helmut F. [Akademischer Betreuer] Schlaak. "Integrierte 3D-Lithium-Ionen-Dünnschichtbatterien: Dünnschichtkathoden auf strukturierten Substraten und elektrochemische Eigenschaften / Laura Bohne. Betreuer: Wolfram Jaegermann ; Helmut F. Schlaak." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2012. http://d-nb.info/1106114965/34.
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Hallot, Maxime. "Micro-batteries tout solide en technologie Li-ion sur substrats Silicium planaires et tridimensionnels pour objets connectés." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I115.
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La miniaturisation des appareils connectés (Internet des objets, IoT) s'accompagne d'une réduction de l'espace pour les systèmes de stockage de l'énergie conventionnels (piles et batteries). Pour pallier à ce problème et pouvoir étendre de larges réseaux de capteurs communicants, il est indispensable de repenser l'architecture des micro-batteries en passant par des configurations 3D tout solide en technologie Lithium-ion. L'objectif de ces travaux est de synthétiser des matériaux de batteries par des techniques de dépôt couches-minces pouvant convenir à ces architectures tridimensionnelles: le dépôt par couche atomique (ALD). La synthèse s'accompagne de techniques de caractérisations avancées des matériaux de batteries permettant de remonter aux propriétés électrochimiques et structurales des éléments de la batterieMiniaturized sensors for Internet of Things (IoT) application is in expansion since the last 10 years. All solid-state lithium-ion battery is a promising candidate. Nevertheless, in spite of high technological readiness level, planar micro-batteries suffer from a lack of energy density meaning that it is necessary to develop new architectures to fullfill the performances requirements. 3D structures is needed for such application and this work is focused on the synthesis of positives electrodes with high storage capacity and high operating voltage by Atomic layer deposition (ALD). In the frame of this work,we will rely structurals and electrochemicals properties by differents characterisations techniques for batteries materials
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Denoyelle, Elise. "Développement d’une microbatterie Li-ion 3D & Étude d’une anode de silicium amorphe déposée par LPCVD sur substrat 3D." Caen, 2010. http://www.theses.fr/2010CAEN2005.
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Depuis l’avènement des premiers circuits intégrés, l’industrie du semiconducteur s’efforce sans cesse de miniaturiser la taille des composants électroniques. La société NXP conçoît depuis plusieurs années des systèmes "sb-SiP" (silicon-based System in Package) qui permettent d’intégrer les composants passifs sur une puce passive sur laquelle est montée une ou plusieurs puces actives. Ce concept repose principalement sur la technologie PICS (Passive Integration Connective Substrate) qui permet d’intégrer sur silicium des condensateurs de valeurs élevées. Devant le succès et le potentiel de ce procédé, NXP entrevoit de nouvelles applications comme les microbatteries 3D lithium-ion. Dans un premier temps, nous avons effectué une recherche de partenariat afin d’acquérir l’expertise nécessaire dans la technologie lithium-ion. Les différentes démarches investies nous ont permis de définir plus précisément les briques technologique intervenant dans le développement d’une microbatterie 3D sur substrat silicium et d’aborder le second axe de ces travaux: l’étude d’une anode de silicium amorphe déposée par LPCVD (Low Pressure Chemical Vapor Deposition). L’objectif de l’étude est d’évaluer les performances d’une anode en silicium amorphe en configuration planaire (2D) et tridimensionnelle (3D)Since the first Integrated Circuits, the Semiconductors industry has innovated in the field of miniaturization at the device level. For several years, NXP company has designed sb-SiP systems (silicon-based System in Package) which allow the insertion of passive components into passive devices on which an active device is mounted. The concept depends upon the PICS technology (Passive Integration Connective Substrate) which allows the integration of capacitors of high values. Considering the achievement of this process, NXP wishes to develop new products as 3D Li-ion microbatteries. At first, we developed a partnership approach in order to acquire competences in lithium-ion technology. The different contacts allow us to define more precisely the technological components needed in order to create a 3D-microbattery on silicon substrate. In a second part, we adress the study of an amorphous silicon thin film anode deposited by LPCVD (Low Pressure Chemical Vapor Deposition). The objective of the study is to measure the electrochemical performances of the amorphous silicon anode on 2D and 3D silicon substrate
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Jones, Jessica C. "Atomic Layer Deposition of H-BN(0001) on Transition Metal Substrates, and In Situ XPS Study of Carbonate Removal from Lithium Garnet Surfaces." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703333/.
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The direct epitaxial growth of multilayer BN by atomic layer deposition is of critical significance forfo two-dimensional device applications. X-ray photoelectron spectroscopy (XPS) and low energy electron diffraction (LEED) demonstrate layer-by-layer BN epitaxy on two different substrates. One substrate was a monolayer of RuO2(110) formed on a Ru(0001) substrate, the other was an atomically clean Ni(111) single crystal. Growth was accomplished atomic layer deposition (ALD) cycles of BCl3/NH3 at 600 K substrate temperature and subsequent annealing in ultrahigh vacuum (UHV). This yielded stoichiometric BN layers, and an average BN film thickness linearly proportional to the number of BCl3/NH3 cycles. The BN(0001)/RuO2(110) interface had negligible charge transfer or band bending as indicated by XPS and LEED data indicate a 30° rotation between the coincident BN and oxide lattices. The atomic layer epitaxy of BN on an oxide surface suggests new routes to the direct growth and integration of graphene and BN with industrially important substrates, including Si(100). XPS and LEED indicated epitaxial deposition of h-BN(0001) on the Ni(111) single crystal by ALD, and subsequent epitaxially aligned graphene was deposited by chemical vapor deposition (CVD) of ethylene at 1000 K. Direct multilayer, in situ growth of h-BN on magnetic substrates such as Ni is important for spintronic device applications. Solid-state electrolytes (SSEs) are of significant interest for their promise as lithium-ion conducting materials but are prone to degradation due to lithium carbonate formation on the surface upon exposure to atmosphere, adversely impacting Li ion conduction. In situ XPS monitored changes in the composition of the SSE Li garnet (Li6.5La3Zr1.5Ta0.5O12, LLZTaO) upon annealing in UHV and upon Ar+ ion sputtering. Trends in core level spectra demonstrate that binding energy (BE) calibration of the Li 1s at 56.4 eV, yields a more consistent interpretation of results than the more commonly used standard of the adventitious C 1s at 284.8 eV. Annealing one ambient-exposed sample to >1000 K in UHV effectively reduced surface carbonate and oxygen, leaving significant amounts of carbon in lower oxidation states. A second ambient-exposed sample was subjected to 3 keV Ar+ ion sputtering at 500 K in UHV, which eliminated all surface carbon, and reduced the O 1s intensity and BE. These methods present alternative approaches to lithium carbonate removal than heating or polishing in inert atmospheres and are compatible with fundamental surface science studies. In particular, the data show that sputtering at mildly elevated temperatures yields facile elimination of carbonate and other forms of surface carbon. This is in contrast to annealing in either UHV or in noble gas environments, which result in carbonate reduction, but with significant remnant coverages of other forms of carbon.
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Brigouleix, Catherine. "Elaboration et étude de couches minces électrochromes déposées par pulvérisation cathodique. Mise en oeuvre de démonstrateurs sur substrat flexible." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2004. http://tel.archives-ouvertes.fr/tel-00005358.
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L'objectif de la thèse est d'étudier des dispositifs électrochromes sur support flexibles. Ces systèmes ont une transmission dans le visible et le proche infra-rouge qui peut être modulée sous l'effet d'une tension électrique. Ils sont constitués d'un empilement de couches minces : - un film électrochrome à coloration cathodique à base de WO3, - une couche conductrice ionique au lithium, inorganique (LiPON) ou organique gélifiée, - une contre-électrode à coloration anodique ("LixNi0.5O") ou optiquement passive (V2O5). Cet ensemble, compris entre deux électrodes conductrices transparentes est déposé sur PET. Les couches électrochromes et l'électrolyte inorganique sont déposés par pulvérisation cathodique. La corrélation entre paramètres de dépôt, propriétés électrochromes et propriétés structurales a été établie.
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Létiche, Manon. "Élaboration de matériaux pour microbatterie 3D Li-ion par dépôt de couches atomiques (ALD) et caractérisations structurales operando." Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10183/document.
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Afin de subvenir aux besoins énergétiques des nouvelles technologies électroniques nomades et miniatures, le développement de microdispositifs de stockage électrochimique d’énergie suffisamment performants telles que les microbatteries (MB) Li-ion est nécessaire. Pour ce faire, l’élaboration de MB Li-ion en topologie tridimensionnelle est une voie attractive qui permet le déploiement de surface spécifique tout en conservant l’empreinte surfacique initiale (de l’ordre du mm2), exacerbant ainsi la densité d’énergie délivrée par la MB. Cette solution est rendue possible grâce au développement de technique de dépôt couches minces telle que l’ALD qui est capable de réaliser des dépôts conformes. Dans le cadre de cette thèse, un électrolyte solide (Li3PO4) a été développé et optimisé de façon conforme, par ALD, sur un substrat de silicium structuré au préalable par des techniques de micro-fabrication. Une électrode positive de type spinelle (LiMn1.5Ni0.5O4) a également été élaborée par pulvérisation cathodique RF. Les performances ont été optimisées en fonction des paramètres de dépôt sur un substrat Si/Al2O3/Pt. Une capacité volumique de 63 µAh.cm-2.µm-1 a ainsi été mesurée pour un dépôt de 420 nm à 0,01 mbar recuit sous air à 700°C. Enfin, un prototype de cellule électrochimique en vue d’un suivi in situ/operando par DRX d’une électrode en couche mince, a été proposéIn order to address the demand on energetic needs to sustain nomad and miniaturized electronic devices, micro-devices performance for energy storage such as Li-ion microbatteries (MB) have to be improved. An attractive way to meet the required performance consists in using 3D topology increasing the specific surface while keeping the initial surface footprint (in the mm2 range) which is significantly enhancing the delivered energy density of the MB. The development of thin film technologies such as ALD enabling conformal deposition makes it possible. In the framework of this thesis, a solid electrolyte (Li3PO4) has been developed and optimized by ALD, on a 3D micro-architectured silicon substrate obtained by microfabrication techniques. A positive electrode (LiMn1.5Ni0.5O4) has also been developed and optimized as a function of the deposition parameter by RF sputtering deposition on a Si/Al2O3/Pt substrate. A volumetric capacity of 63 µAh.cm-2.µm-1 has been measured for a film of 420 nm thick obtained at 0.01 mbar and then annealed at 700°C under air atmosphere. Finally, a prototype has been proposed to realize an electrochemical cell for the purpose of in situ/operando follow-up by XRD of a thin film electrode deposited on silicon substrate
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Braun, Loïc. "Composants à ondes élastiques de surface pour le filtrage à gabarits maîtrisés aux fréquences radios pour applications spatiales et professionnelles." Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2020/document.
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Ce mémoire traite de l’ étude et de la réalisation de composants à ondes élastiques de surface (SAW) pour des applications de filtrage dans les gammes VHF et UHF. Nous y étudions différentes structures de ces filtres, à commencer par des filtres à couplage acoustique longitudinal centrés aux alentoursdu gigahertz, de bande passante relative inférieure à 0,1 % réalisés sur quartz. Leur fabrication et leur caractérisation ont révélé des pertes d’insertion inférieures à 5 dB et des niveaux de rejet supérieurs à 20 dB, conformément aux prévisions de notre modèle de matrice mixte. Un tel filtre a été inséré dans un oscillateur pour valider la fonction réalisée. Pour une maîtrise accrue de la conception de ces filtres, nous avons développé un modèle tenant compte de la contribution des modes transverses sur leur fonction de transfert. Des comparaisons entre théorie et expérience ont permis de démontrer la précision de ce modèle. Nous nous sommes également intéressés à des structures de filtres à éléments d’impédance et à transducteurs en éventails (fan-shaped) pour la réalisation de bandes passantes relatives comprises entre 1 et 15 % dans la bande 100 − 300 MHz. Pour chacune de ces structures, nous avons développé un modèle permettant d’en étudier le comportement. Une configuration de filtre en treillis de bande passante relative proche de 2 %a été fabriquée et caractérisée, ainsi que plusieurs filtres à transducteurs en éventails de bandes passantes relatives supérieures à 10 %. Enfin, nous avons étudié deux approches qui nous ont permis de réaliser des dispositifs fonctionnant à des fréquences voisines de 3 GHz. La première, consiste à exploiter les vitesses de phase supérieures à 5 km.s−1 d’un guide d’ondes à base de carbone-diamant. La seconde exploite la résolution d’un procédé de lithographie par nano-impression pour réduire la période des réseaux d’ électrodesThis thesis deals with the development of surface acoustic wave devices (SAW) for filtering applications in the VHF and UHF bands. Several filter structures are studied. The first ones are longitudinally coupled resonator filters (LCRF) manufactured on Quartz with a relative pass-band narrower than 0,1 % centered at about 1 GHz. These filters have been fabricated and characterized, yielding less than 5 dB insertion loss with rejection levels in excess of 20 dB as predicted by our P-matrix model. One of these filters has been mounted in an oscillator to validate its characteristics.To improve the design of such filters, we have developed a model accounting for transverse mode contributions on their spectral function. Comparisons between theory and experiment emphasizes the accuracy of the developed model. We also have investigated impedance element and slanted transducers (fan-shaped) filter structures to produce filters with relative pass-band ranging from 1 to 15 % in the 100 − 300 MHz frequency range. For each type of filters, we have developed a model to predict their electrical response. A balanced-bridge filter configuration with a 2 % relative pass-band and four fan-shaped filters with pass-band larger than 10 % have been fabricated and characterized. Finally, we have studied two approaches for the development of SAW devices operating at frequencies in the vicinity of 3 GHz. The first approach exploits Diamond-based substrates, providing phase velocity higher than 5 km.s−1. The second one uses a nano-imprint lithography process to reduce the pitch of electrode gratings
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ROSSI, FEDERICO. "Study of exopolysaccharide-producing cyanobacteria in biofilm growing on lithic substrate and in extreme environments." Doctoral thesis, 2010. http://hdl.handle.net/2158/547903.
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Chen, Yen-ming, and 陳彥名. "Molecular beam epitaxial growth of nonpolar ZnO on lithium aluminate substrate." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/31570381553949354041.
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碩士國立中山大學
材料與光電科學學系研究所
100
Both non-polar (10-10) (m-plane) and polar (0001) (c-plane) zinc oxide (ZnO) have a good lattice match with lithium aluminum (LiAlO2, LAO) (200) substrate, so it is difficult to control the epitaxial orientation. Therefore, this research is to explore how the growth parameters influence on the crystal orientation of ZnO film grown by plasma assisted molecular beam epitaxy. The experimental results show that m-plane ZnO can be grown with low zinc flux and low oxygen pressure. Increasing zinc flux and oxygen pressure will lead to increase in growth rate, and consequently, c-plane ZnO will nucleate on the substrate besides m-plane zinc oxide. The substrate temperature is one of the main factors that influence the choice of zinc oxide epitaxial orientation. High temperature will promote the m-plane zinc oxide nucleation, while low temperature will conduct to the c-plane zinc oxide nucleation. Under low zinc flux and low oxygen pressure, epitaxy of ZnO with different crystalline orientations can be achieved through changing the substrate temperature. The surface morphology and roughness of the substrate will affect the particle size and surface morphology of ZnO epilayers. When the substrate is smooth, the crystal size of the epitaxial film is large and the surface is flat with many rectangular stripes, taking on the platform-like morphology. If the substrate is rough with many scratches, the particle size becomes small and the surface is granular-like and rather rough. Furthermore, when the substrate is rough, it is difficult to control the different orientations of ZnO epitaxial films through changing the substrate temperature.
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Stone, Barbara Ann. "Physical characterization of lithium niobate thin films on silicon substrates." Thesis, 1988. http://hdl.handle.net/1911/13320.
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The structure and orientation of radio frequency sputtered lithium niobate (LiNbO$\sb3$) films on silicon substrates is determined using x-ray diffraction. The structure of the LiNbO$\sb3$ films is determined to be a strong function of the substrate temperature. The preferred crystal orientation of the film is found to depend on the substrate orientation. Of particular importance is the observation of LiNbO$\sb3$ polycrystalline films oriented with the c axis of the crystallites normal to the surface of $\langle$111$\rangle$ silicon substrates. This result is important since the ferroelectric polarization and photocurrents are directed along the c axis of crystal, making the development of ferroelectric memory devices using LiNbO$\sb3$ possible. Scanning electron microscopy revealed that the films were generally smooth, and no ferroelectric domain contrast was observed. Ellipsometry was used to determine the refractive indices and thicknesses of the films.
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Wang, Shunxi. "Lithium niobate thin films on diamond substrates for SAW devices." Thesis, 2001. http://hdl.handle.net/1911/18047.
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Lithium niobate thin films have been grown on diamond/silicon substrates by metallo-organic decomposition and radio frequency (R. F.) magnetron sputtering. The surface acoustic wave (SAW) characterizations of the multilayer lithium niobate/diamond/silicon are calculated. The lithium niobate thin films as well as the diamond/silicon substrates are structurally analyzed using techniques such as Bragg X-ray diffraction, scanning electron microscopy, atomic force microscopy, electron microprobe, and Raman spectroscopy to determine their crystal structure, surface morphology and composition distribution. With the use of a lift-off photolithography planar process, surface acoustic wave filter devices on substrates such as lithium niobate single crystal plates, zinc oxide/diamond/silicon, and lithium niobate/diamond/silicon, are fabricated. Microwave characterizations, such as the frequency response, of these filters are measured, and their impulse response in the time domain are obtained by fast Fourier transformation. SAW activities for LiNbO3/diamond/silicon structure are observed. Discussions about the results and further improvements are presented.
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Huang, Hung-Jia. "Optical characterization of lithium niobate thin film waveguides sputtered on sapphire substrates." Thesis, 1991. http://hdl.handle.net/1911/13528.
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Thin films of lithium niobate on various oriented sapphire substrates were fabricated by the rf sputtering method. Polarized He-Ne laser light with a wavelength of 6328 A was successfully coupled into the optical waveguides by a rutile prism coupler. A description of the prism coupler used for this research is given. The guided modes excited by the prism coupler were observed and used to examine the optical properties of the waveguide. The refractive indices and thicknesses of various samples were calculated and tabulated. The birefringence observed in the films and x-ray diffraction studies have confirmed the polycrystalline nature of the films. The attenuation of the light propagating in various (zeroth- to second-order) waveguide modes was determined to be in the range of 1.1 to 1.3 $\pm$ 0.1 dB/cm.
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Bohne, Laura. "Integrierte 3D-Lithium-Ionen-Dünnschichtbatterien: Dünnschichtkathoden auf strukturierten Substraten und elektrochemische Eigenschaften." Phd thesis, 2012. https://tuprints.ulb.tu-darmstadt.de/2957/1/Dissertation_LB_web.pdf.
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Das wachsende Interesse an autonomen Mikrosystemen, die den Menschen im Alltag unterstützen sollen, führt zu einem steigenden Bedarf an Mikrobatterien mit hoher Leistungsdichte und Kapazität bei immer kleinerer verfügbarer Grundfläche. Im Gegensatz zu herkömmlichen zweidimensionalen Lithium-Ionen-Dünnschichtbatterien, die eine vergleichsweise geringe Kapazität und Leistung bezogen auf ihre Grundfläche aufweisen, erlauben es dreidimensionale Dünnschichtbatterien, diesem Trend gerecht zu werden. In der vorliegenden Arbeit wird der Übergang von zweidimensionalen zu integrierten, dreidimensionalen Dünnschichtbatterien mittels Abscheidung des Kathodenmaterials LiCoO2 auf planaren sowie strukturierten Substraten beschrieben.
Nach Aufarbeitung des Standes der Technik dreidimensionaler Mikrobatterien wird vor dem Hintergrund der Integration einer Mikrobatterie auf der Rückseite eines Siliziumchips ein geeignetes Konzept ausgewählt, das auf der Verwendung eines vorstrukturierten Siliziumsubstrats in Kombination mit einem Festkörperelektrolyten beruht. Bei der Auswahl der Materialien für die benötigten Batterieschichten wird nach Möglichkeit auf Standardprozesse der Halbleiterindustrie zurückgegriffen. Zur Herstellung des Dünnschichtkathodenmaterials LiCoO2 wird im Zentralbereich Forschung und Vorausentwicklung der Robert Bosch GmbH ein Prozess etabliert, der aus einer Abscheidung durch RF-Magnetron-Sputtern sowie anschließendem Tempern der gesputterten Schichten besteht. Es wird nachgewiesen, dass die prozessierten LiCoO2-Schichten stöchiometrisch sind und die geforderte hexagonale Schichtstruktur mit (003)-Vorzugsorientierung aufweisen.
Für die Herstellung von dreidimensionalen Dünnschichtbatterien wird neben konformen Abscheideverfahren auch eine geeignete Substratstrukturierung benötigt, die bei gegebener projizierter Grundfläche zu einer Maximierung der Kapazität und Leistungsdichte führt. Es werden verschiedene Strukturvarianten diskutiert, aus denen drei unter Berücksichtigung prozesstechnischer Randbedingungen ausgewählt und experimentell untersucht werden: Im DRIE-Prozess hergestellte Gräben mit senkrechten Seitenwänden, durch Ätzen mit KOH erzeugte Strukturen mit pyramidenförmigem Querschnitt sowie in einem zweistufigen Trockenätzprozess hergestellte Gräben mit trichterförmigem Querschnitt. Unter Berücksichtigung der für diese Arbeit verfügbaren Prozesstechnologien stellen letztere einen guten Kompromiss zwischen erreichbarer Kantenbedeckung und Oberflächenvergrößerung für dünne LiCoO2-Schichten dar.
Die hergestellten zwei- und dreidimensionalen Dünnschichtkathoden werden in Swagelok-Zellen elektrochemisch charakterisiert und miteinander verglichen. Da die LiCoO2-Schichten mittels Sputtern abgeschieden werden, ist das abgeschiedene Materialvolumen auf planaren und strukturierten Substraten bei identischen Sputterbedingungen gleich und somit auch die erzielbare Kapazität. Dennoch kann die erwartete Tendenz, aufgrund einer größeren aktiven Oberfläche von strukturierten Substraten eine höhere Leistungsdichte zu erzielen, nachgewiesen werden.
Die Ergebnisse dieser Arbeit zeigen einen Schritt auf dem Weg zu integrierten, dreidimensionalen Mikrobatterien auf und stellen damit eine gute Basis für die Weiterarbeit an dreidimensionalen Festkörperdünnschichtbatterien dar. Hierfür werden weiterführende Ansätze abgeleitet, von denen insbesondere die konforme Abscheidung der aktiven Batterieschichten im CVD-Verfahren auf mit hohem Aspektverhältnis strukturierten Substraten die Realisierung unterschiedlichster, autonomer Mikrosysteme mit integrierter Mikrobatterie verspricht.
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Huang, Hsin-Shun, and 黃新舜. "Design and Fabrication of Ridge-type Directional Coupler on Gamma-ray Irradiated Lithium Niobate Substrate." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/98144096587498236544.
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碩士國立臺灣大學
光電工程學研究所
99
In this thesis, ridge waveguides are fabricated by using proton exchange and wet etching in gamma-ray irradiated lithium niobate(LiNbO3). Experimental results show the depths and aspect ratios of ridge structures are all improved, which gives rise to optical fields of higher aspect ratios and electro-optic modulators with better characteristics. The ridge structures are obtained by proton exchange for 8 hr with various acid sources and etched for 8 hr with a mixture of hydrofluoric acid and nitric acid. The deepest depth and the aspect ratio of ridge structure are 4.472μm and 1.3 when the dosage of gamma-ray irradiation is 162.5krad. Moreover, the coupling length is shortened by 8.2% when a ridge-type directional coupler is fabricated with gamma-ray irradiated lithium niobate, which indicates that coupling effect is enhanced due to gamma-ray irradiation. And the half-wave voltage is decreased by 37.94%, and the extinction ratio is increased by 46.54%. Thus, it shows that gamma-ray irradiation is advantageous for the improvement of lithium niobate integrated optical waveguides.
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Lin, Albert Jian. "Lithium niobate thin films deposited on silicon substrates for SAW applications (surface acoustic wave)." Thesis, 1996. http://hdl.handle.net/1911/14063.
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Lithium niobate has a number of attractive piezoelectric and ferroelectric properties that have been exploited for several different applications. The main purpose of this work is to produce lithium niobate thin films on silicon substrates (with amorphous SiO$\sb2$ coating) and to make low insertion loss surface acoustic wave (SAW) devices. For SAW devices, the insertion loss mainly relates to the electromechanical coupling coefficient (K$\sp2$) of the materials. To get low insertion loss in SAW devices, we need use high K$\sp2$ materials. Among common piezoelectric materials, lithium niobate has the highest K$\sp2$ value. Theoretical curves of SAW properties of lithium niobate bulk crystals and films on SiO$\sb2$(amorphous)/Si(100) were obtained. Thin films of lithium niobate have been deposited on SiO$\sb2$(amorphous)/Si(100) substrates by rf magnetron sputtering. The film samples were structurally analyzed by x-ray diffraction (XRD). Lithium niobate XRD peaks (012), (104) and (110) were identified. Highly textured lithium niobate film samples with very good transparency and uniformity were obtained.
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Li, Yu-Zhi, and 李育誌. "Periodic Segmented Waveguides and Ridge Optical Waveguides Based on Z-cut Lithium Niobatgte Substrates." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/05646476412629395757.
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碩士大同大學
光電工程研究所
90
In this thesis, the proton-exchanged technique is used to fabricate several waveguide on z-cut Lithium Niobate substrates . This technique has the advantages such as simple treatment, low loss and low cost. At the same time, we also use the Inductively Coupled Plasma Reactive Ion Etching, ICP-RIE to etch the Lithium Niobate. By mixture of 、Ar and . We find that if we input different proportion of Hydrogen, we can get the different etching rate and it also affects the roughness of the etched surface. Finally we also take use of the technique to fabricate the ridge-type waveguide. Both theoretical analysis and experimental measurement has been carried out for the comparison. In this thesis, the near-field(NF) method is applied to the index profile measurement. However, there exist noise problem. We propose the use of a field function calculated by variation method to smooth the measured intensity profile without or loss of accuracy. A new trial field, namely, the modified Hermite-Gauss (MHG) function has been used. We have coupled laser beam(at 0.6328 μｍ wavelength) into devices by virtue of the end-fire coupling method, have also verified the therries .
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Rua, João Luís dos Santos Heleno da. "Baterias de lítio em filme fino: fabrico e caracterização de LiCoO2 para utilização no cátodo." Master's thesis, 2015. http://hdl.handle.net/1822/47229.
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Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e ComputadoresEsta dissertação inclui a deposição e caracterização do Óxido de Lítio Cobalto (LiCoO2) para utilização como cátodo de uma bateria de lítio em filme fino recarregável e flexível. Atualmente, a maior desvantagem desta tecnologia de baterias é a capacidade reduzida. Com este trabalho pretende-se investigar processos de melhoria da capacidade e durabilidade das baterias de lítio em filme fino, passando pelo aumento dos números de ciclos de cargas/ descargas que as baterias conseguem realizar até à sua degradação. Um desses processos consiste na tentativa de obter filmes de LiCoO2 com uma determinada orientação estrutural a temperatura reduzida (~400 ºC), temperatura esta compatível com o substrato flexível de Kapton® utilizado. Para isso recorreu-se, a dois tipos de tratamento térmico: recozimento dos filmes de LiCoO2 num forno convencional e recozimentos dos mesmos por via laser. Outro processo consiste na tentativa de aumentar a área de contacto entre os vários filmes constituintes de uma bateria (sem aumentar as dimensões da bateria), através da incidência do feixe laser num substrato de Kapton®. Para além disto, o ânodo de lítio foi substituído pelo ânodo de germânio que possui uma elevada capacidade gravimétrica (1384 mAh/g) [1], uma elevada difusão de iões de lítio, alta capacidade de inserção/extração de iões de lítio e consegue suportar elevadas taxas de carga/descarga, conduzindo a um melhor desempenho na ciclagem da bateria. A bateria a fabricar será constituída por um substrato de Kapton® 500HN; uma camada de Si3N4, um filme fino de LiCoO2 como cátodo e um filme de LiPON como eletrólito depositados por RF sputtering. O ânodo, inicialmente, foi um filme fino de lítio depositado por evaporação térmica e posteriormente utilizou-se germânio depositado por e-beam. Os contactos são platina depositada por DC sputtering e titânio depositado por e-beam. Para caracterização da bateria recorreu-se a análises de ciclos de carga/descarga utilizando o potencióstato Gamry 600; AFM e microscopia ótica para o substrato de Kapton®; espectroscopia Raman para os filmes de LiCoO2 com recozimento a laser e análises num microscópio SEM para verificar a adesão dos filmes finos.
This dissertation includes the deposition and carachterization of Lithium Cobalt Oxide (LiCoO2) as a cathode on a thin-film lithium-ion rechargeable battery in a flexible substrate. Nowadays, the biggest flaw in this battery technology is its low capacity. This work’s intention is to investigate new processes to improve the capacity and durability of thin-film lithium-ion batteries by increasing its cyclability untill its degradation.One of these processes consists in the attempt to obtain thin films of LiCoO2 with a certain structural orientation on a low temperature (~400 ºC), which is compatible with the Kapton® flexible substrate used.Two types of thermal treatments were used to achieve that: conventional furnace annealing and laser annealing. Another process consists in the attempt to increase the surface area between the many thin-film that form the battery (without increasing the battery’s dimensions), by using a laser to create patterns in the Kapton® substrate. Besides, the anode material (lithium metal) was replaced by germanium, which has a high gravimetric capacity (1384 mAh/g)[1], a high lithium ions difusion, high capacity of lithium ions insertion and extraction and is able to support high charging/discharging rates, which leads to a better performance in the battery’s ciclabillity. The fabricated battery had a Kapton® 500HN substrate; Si3N4, LiCoO2 (as cathode) and LiPON (as electrolyte) thin films deposited by RF sputtering. The anode, initialy, was a lithium thin film deposited by thermal vaporization, but later it was switched to germanium deposited by e-beam.The current collectors are: a Pt thin film deposited by DC sputtering (for the cathode) and a Ti thin film (for the anode) deposited by e-beam. As characterization it will be used the Gamry 600 potentiostate to cycle the battery; AFM and optical microscopy for the Kapton® substrate; Raman spectroscopy for the laser annealed LiCoO2 thin films and SEM analysis of the whole battery to analise the adhesion of the thin films.
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"Finite Element Analysis of Silicon Thin Films on Soft Substrates as Anodes for Lithium Ion Batteries." Master's thesis, 2011. http://hdl.handle.net/2286/R.I.8896.
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abstract: The wide-scale use of green technologies such as electric vehicles has been slowed due to insufficient means of storing enough portable energy. Therefore it is critical that efficient storage mediums be developed in order to transform abundant renewable energy into an on-demand source of power. Lithium (Li) ion batteries are seeing a stream of improvements as they are introduced into many consumer electronics, electric vehicles and aircraft, and medical devices. Li-ion batteries are well suited for portable applications because of their high energy-to-weight ratios, high energy densities, and reasonable life cycles. Current research into Li-ion batteries is focused on enhancing its energy density, and by changing the electrode materials, greater energy capacities can be realized. Silicon (Si) is a very attractive option because it has the highest known theoretical charge capacity. Current Si anodes, however, suffer from early capacity fading caused by pulverization from the stresses induced by large volumetric changes that occur during charging and discharging. An innovative system aimed at resolving this issue is being developed. This system incorporates a thin Si film bonded to an elastomeric substrate which is intended to provide the desired stress relief. Non-linear finite element simulations have shown that a significant amount of deformation can be accommodated until a critical threshold of Li concentration is reached; beyond which buckling is induced and a wavy structure appears. When compared to a similar system using rigid substrates where no buckling occurs, the stress is reduced by an order of magnitude, significantly prolonging the life of the Si anode. Thus the stress can be released at high Li-ion diffusion induced strains by buckling the Si thin film. Several aspects of this anode system have been analyzed including studying the effects of charge rate and thin film plasticity, and the results are compared with preliminary empirical measurements to show great promise. This study serves as the basis for a radical resolution to one of the few remaining barriers left in the development of high performing Si based electrodes for Li-ion batteries.Dissertation/Thesis
Appendix H - Movies (zipped)
M.S. Mechanical Engineering 2011
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Tsai, Chih-Hao, and 蔡志豪. "The effect of lithium manganese oxide as thin film positive electrodes by annealing treatment and substrate bias assisted sputtering." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/82263149598462231145.
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碩士逢甲大學
材料科學所
92
Abstract Secondary lithium batteries have been the primary power supply components for various portable electronic devices, such as cell phones and notebook computers. However, as the weight and volume of the portable devices continuously decrease, the search for smaller, lighter, and higher-power-density sources has never stopped. In order to meet these requirements, the concept of Thin Film Batteries (TFB), or all solid state micro-batteries, has therefore been of great interest. With only a few micron meters of thickness or less, thin film batteries are compatible with micron electro-mechanical devices, and can be the back-up power for SRAM, as well. This research uses LiMn2O4 as cathode material of thin film batteries. The applied substrate bias during sputtering of LixMn2-yO4 thin film will control the ion-bombarding energy and achieve the in-situ modification. Moreover, the air annealing will improve the properties of LixMn2-yO4 thin film, such as the capacity, discharge voltage and electric conductivity. The result shows that bias -20VDC will deposit LixMn2-yO4 film with some appropriate defects. These defects are expected to provide a flexible space which can help to maintain the spinel structure. These films have better cycle life and their discharge capacity can reach 122 mAh/g. The 600℃-1hr air annealing can increase effectively the characteristic of 0VDC deposited LixMn2-yO4 films. These air-annealed films can have a perfect spinel structure and exhibit a two-stage discharge voltage plate（4.1 and 3.9V）.
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"Study on Buckling of Stiff Thin Films on Soft Substrates as Functional Materials." Doctoral diss., 2014. http://hdl.handle.net/2286/R.I.24814.
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abstract: In engineering, buckling is mechanical instability of walls or columns under compression and usually is a problem that engineers try to prevent. In everyday life buckles (wrinkles) on different substrates are ubiquitous -- from human skin to a rotten apple they are a commonly observed phenomenon. It seems that buckles with macroscopic wavelengths are not technologically useful; over the past decade or so, however, thanks to the widespread availability of soft polymers and silicone materials micro-buckles with wavelengths in submicron to micron scale have received increasing attention because it is useful for generating well-ordered periodic microstructures spontaneously without conventional lithographic techniques. This thesis investigates the buckling behavior of thin stiff films on soft polymeric substrates and explores a variety of applications, ranging from optical gratings, optical masks, energy harvest to energy storage. A laser scanning technique is proposed to detect micro-strain induced by thermomechanical loads and a periodic buckling microstructure is employed as a diffraction grating with broad wavelength tunability, which is spontaneously generated from a metallic thin film on polymer substrates. A mechanical strategy is also presented for quantitatively buckling nanoribbons of piezoelectric material on polymer substrates involving the combined use of lithographically patterning surface adhesion sites and transfer printing technique. The precisely engineered buckling configurations provide a route to energy harvesters with extremely high levels of stretchability. This stiff-thin-film/polymer hybrid structure is further employed into electrochemical field to circumvent the electrochemically-driven stress issue in silicon-anode-based lithium ion batteries. It shows that the initial flat silicon-nanoribbon-anode on a polymer substrate tends to buckle to mitigate the lithiation-induced stress so as to avoid the pulverization of silicon anode. Spontaneously generated submicron buckles of film/polymer are also used as an optical mask to produce submicron periodic patterns with large filling ratio in contrast to generating only ~100 nm edge submicron patterns in conventional near-field soft contact photolithography. This thesis aims to deepen understanding of buckling behavior of thin films on compliant substrates and, in turn, to harness the fundamental properties of such instability for diverse applications.Dissertation/Thesis
Ph.D. Mechanical Engineering 2014