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Paus, K. "The electron microscopy of silicon of sapphire materials." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382598.
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Ullah, Hanif. "Simulation studies of photovoltaic thin film devices." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/48800.
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To cope with energy requirements the utilization of renewable energies, particularly the Sun supplies the biggest and abundant energy source in Earth. Photo-voltaic and solar cell are the well advance and burning technology and a field of hot research. Majority of research centers and universities are working in this field. 1G, 2G, 3G and next generation of photo-voltaic cells have been developed and still to improve its efficiency and to decrease it 0.2 $/W cost.
Our work mainly based on the theoretical and physical analysis of thin-film Photovoltaic devices. We will explore different software used for the analysis of PV cells, and will analyse different simulation related to solar cells like open circuit voltage VOC, Short circuit current JSC, Fill Factor FF (%) and external Quantum efficiency (%) for thin film solar cell including CIGS, CIS, CGS, CdTe, SnS/CdS/ZnO etc. To have different analysis for different combination and different replacement for materials used in the solar cell fabrication. To cope with the PV cost and environmental hazards we have to find alternate solutions.Ullah, H. (2015). Simulation studies of photovoltaic thin film devices [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48800
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Bittau, Francesco. "Analysis and optimisation of window layers for thin film CDTE solar cells." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/32642.
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The work presented in this thesis focuses on the investigation and improvement of the window stack of layers for thin film CdTe solar cells fabricated in the Center for Renewable Energy Systems Technology (CREST) laboratories. In particular the aim was to change the standard structure including TCO, high resistive transparent (HRT)layer and CdS which is limited by the low transparency of the CdS layer, to a better performing one. The first result chapter of the thesis describes the study of ZnO HRT layers. ZnO thin films were deposited by radio frequency (RF) magnetron sputtering with different structural, optical and electrical properties which were characterized by X-ray diffraction, electron microscopy, spectrophotometry, Hall Effect method and 4-point probe. ZnO films were then incorporated in CdTe solar cells with the structure: FTO/ZnO/CdS/CdTe/Au back contact and the performance of these devices were compared with the film properties to single out trends and identify optimal film characteristics. By varying the deposition pressure of ZnO films, it was possible to increase their transparency and significantly increase their resistivity. While better transparency positively affected the solar cell current density output and efficiency, the resistivity of ZnO films did not show any clear impact on device efficiency. By increasing the deposition temperature the ZnO film grain size was increased. Increased FF was observed in devices incorporating ZnO layers with bigger grains, although this gain was partially counterbalanced by the Voc degradation, leading to a limited efficiency improvement. Finally the addition of oxygen had the main effect of increasing the resistivity of ZnO films, similarly to what happened with the increase of the sputtering pressure. In this case however, an improvement of FF, Jsc and efficiency was observed, especially at an O2/Ar ratio of 1%. By simulating the solar cells behavior with SCAPS-1D, it was found that these performance change can be explained by the variation of interface properties, precisely the amount of interface defects, rather than by bulk properties. The study presented in the second result chapter focuses on magnesium-doped zinc oxide (MZO) and the variation of its energy band structure. MZO was initially used as the HRT layer within a solar cell structure: FTO/MZO/CdS/CdTe/Au back contact. Sputtering MZO films with a target containing MgO 11 weight% and ZnO 89 weight% allowed for and increased band gap from 3.3 eV of intrinsic ZnO to 3.65 eV for MZO deposited at room temperature. Increasing the superstrate deposition temperature allowed for a further band gap increase up to 3.95 eV at 400 °C due mainly to an conduction band minimum upward shift. It was highlighted the importance to create a positive conduction band offset with the MZO layer conduction band slightly above the CdS conduction band, with an optimum found in this case to be 0.3 eV (efficiency 10.6 %). By creating a positive conduction band offset all the performance parameters (Voc, FF, Jsc, efficiency) significantly increased. One of the reasons for this improvement was found to be a diminished interface recombination due to a more ideal MZO/CdS band alignment. In the second part of this investigation the MZO was used as a replacement for the CdS in a simplified structure: FTO/MZO/CdTe/Au back contact. The concepts used to optimise the performance of these devices also involved tuning the conduction band alignment between MZO/CdTe and efficiencies of 12.5 % were achieved with a at conduction band offset. The efficiency increase was achieved mainly thanks to a better transparency of the MZO layer and a higher Jsc output, compared to devices using a CdS buffer layer. The MZO buffers have been tested in combination with different TCOs. Results are presented in the third result chapter and showed that AZO is a good alternative to FTO working effectively in combination with MZO. AZO/MZO efficiency thin film CdTe solar cells (12.6%, compared to 12.5% with FTO). It was found that increasing the IR transparency of the TCOs leads to a potentially higher Jsc. Achieving a better transparency was obtained by using TCOs with high mobility and lower carrier concentration (AZO and ITiO) and also by using a boro-aluminosilicate glass with low iron content. ITiO yielded the best opto-electrical properties among all the TCO materials. Devices incorporating ITiO however, showed lower performance then those using FTO and AZO. ITO/MZO windows also yielded poor performance. In addition, the ITO films deposited had a high carrier concentration leading to a high NIR absorption by plasma resonance and resulted not ideal for application in thin film CdTe PV.
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Krupa, Katarzyna. "Opto-numerical analysis of AIN piezoelectric thin film operating as an actuation layer in MEMS cantilevers." Phd thesis, Université de Franche-Comté, 2009. http://tel.archives-ouvertes.fr/tel-00544852.
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L'objectif de ce mémoire de thèse consiste à étudier et caractériser les propriétés de couche mince piézoélectrique de nitrure d'aluminium (AlN) utilisées comme une couche d'actionnement de micropoutres multimorphes actionnées piézoélectriquement et à évaluer leurs performances micromécaniques. Ce travail a été effectué en utilisant une méthodologie hybride basée sur l'interaction entre le modèle physique et mathématique des objets étudiés. Ces recherches ont été faites dans le cadre d'une thèse de doctorat effectuée en cotutelle entre l'Université de Franche-Comté et l'Université Technologique de Varsovie. Les deux laboratoires qui ont porté ce projet sont le Département d'Optique P.M. Duffieux de l'Institut FEMTO-ST et l'Institut de Micromécanique et Photonique. Une méthodologie hybride opto-numérique a été proposée pour étudier des microstructures. Cette méthodologie permet la caractérisation complèxe de ces échantillons en identifiant les divergences entre leur modèle physique et mathématique. Cette approche hybride, combinant les données expérimentales obtenues par l'interféromètrie optique et les techniques de nanoindentation avec les résultats de traitements numériques et les équations analytiques, a été appliquée pour étudier les micropoutres silicium où un film mince piézoélectrique d'AlN a été déposé entre les deux électrodes métalliques. Grâce à ces interractions, les propriétés de films AlN ainsi que les comportements micromécaniques de transducteurs piézoélectriques et leur fiabilité ont été déterminés. Nous avons bati un modèle physique de ces dispositifs multimorphes en utilisant la plateforme de métrologie basée sur l'interféromètre de Twyman-Green, offrant les avantages de mesure non-destructive et la haute résolution de techniques optiques. Ainsi, nous avons obtenu des données caractérisant les comportements statiques et dynamiques de micropoutres AlN, ainsi que les différentes propriétés physiques des éléments étudiés. Enfin, quelques mesures de fiabilité de nos microobjets ont permis l'évaluation de l'impact de certains paramètres géométriques et fonctionnels sur les comportements des échantillons et leur durée de vie. Le modèle mathématique proposé s'appuie à la fois sur l'utilisation d'équations analytiques et le calcul par la Méthode des Éléments Finis faisant appel au logiciel ANSYS. Ces calculs ont tenu compte de l'aspect multicouche des éléments étudiés. Ce travail de modélisation a permis d'identifier les paramètres critiques de ces microactionneurs piézoélectriques à la fois du point de vue dimensionel que matériau et de mieux comprendre leurs mécanismes de vieillisement. Par ailleurs, une étude de fiabilité a aussi été réalisée, en incluant des tests accélérés du vieillissement et de la fatigue, ainsi que une étude de la stabilité opérationnelle. Les résultats obtenus nous ont permis de mieux cerner quels sont les paramètres critiques de dommagement le plus probables de ces microobjets et estimer leur temps de vie. Enfin, l'approche opto-numérique proposée a permis d'identifier les étapes de fabrication critiques des micropoutres d'AlN afin d'optimiser leur fabrication. La méthodologie hybride proposée au cours de la thèse de doctorat a étendu la capacité métrologique des techniques d'interférométrie laser. Elle permet de développer les méthodes pour la caractérisation des microstructures, la détermination de leur fiabilité et l'assistance de leur technologie dans la réalisation des dispositifs fiables des paramètres requis. L'application de cette méthodologie a permis de bien comprendre les propriétés de films d'AlN aussi bien que les performances des micropoutres piézoélectriques. Cela peut effectuer en une augmentation de nombre des applications possibles de ces microstructures d'AlN, en améliorant leur qualité et contrôle.
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Li, Han. "Analysis and Applications of Novel Optical Single - and Multi - Layer Structures." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1450393885.
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Liyanage, Chinthaka. "Specific property analysis of thin-film semiconductors for effective optical logical operations." Connect to full text in OhioLINK ETD Center, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1217089206.
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Ibrahim, Kamarulazizi. "Analysis of amorphous thin-film tandem solar cells and their component layers." Thesis, Heriot-Watt University, 1989. http://hdl.handle.net/10399/923.
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Sharma, Varun. "Evaluation of novel metalorganic precursors for atomic layer deposition of Nickel-based thin films." Master's thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-166627.
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Nickel und Nickel (II) -oxid werden in großem Umfang in fortgeschrittenen elektronischen Geräten verwendet. In der Mikroelektronik-Industrie wird Nickel verwendet werden, um Nickelsilizid bilden. Die Nickelmono Silizid (NiSi) wurde als ausgezeichnetes Material für Source-Drain-Kontaktanwendungen unter 45 nm-CMOS-Technologie entwickelt. Im Vergleich zu anderen Siliziden für die Kontaktanwendungen verwendet wird NiSi wegen seines niedrigen spezifischen Widerstand, niedrigen Kontaktwiderstand, relativ niedrigen Bildungstemperatur und niedrigem Siliziumverbrauchs bevorzugt. Nickel in Nickelbasis-Akkus und ferromagnetischen Direktzugriffsspeicher (RAMs) verwendet. Nickel (II) oxid wird als Transistor-Gate-Oxid und Oxid in resistive RAM genutzt wird. Atomic Layer Deposition (ALD) ist eine spezielle Art der Chemical Vapor Deposition (CVD), das verwendet wird, um sehr glatte sowie homogene Dünnfilme mit hervorragenden Treue auch bei hohen Seitenverhältnissen abzuscheiden. Es basiert auf selbstabschließenden sequentielle Gas-Feststoff-Reaktionen, die eine präzise Steuerung der Filmdicke auf wenige Angström lassen sich auf der Basis. Zur Herstellung der heutigen 3D-elektronische Geräte, sind Technologien wie ALD erforderlich. Trotz der Vielzahl von praktischen Anwendungen von Nickel und Nickel (II) -oxid, sind einige Nickelvorstufen zur thermischen basierend ALD erhältlich. Darüber hinaus haben diese Vorstufen bei schlechten Filmeigenschaften führte und die Prozesseigenschaften wurden ebenfalls begrenzt. Daher in dieser Masterarbeit mussten die Eigenschaften verschiedener neuartiger Nickelvorstufen zu bewerten. Alle neuen Vorstufen heteroleptische (verschiedene Arten von Liganden) und Komplexe wurden vom Hersteller speziell zur thermischen basierend ALD aus reinem Nickel mit H 2 als ein Co-Reaktionsmittel gestaltet. Um die neuartige Vorläufer zu untersuchen, wurde eine neue Methode entwickelt, um kleine Mengen in einer sehr zeitsparend (bis zu 2 g) von Ausgangsstoffen zu testen. Diese Methodologie beinhaltet: TGA / DTA-Kurve analysiert der Vorstufen, thermische Stabilitätstests in dem die Vorläufer (<0,1 g) wurden bei erhöhter Temperatur in einer abgedichteten Umgebung für mehrere Stunden wurde die Abscheidung Experimenten und Film Charakterisierungen erhitzt. Die Abscheidungen wurden mit Hilfe der in situ Quarzmikrowaage überwacht, während die anwendungsbezogenen Filmeigenschaften, wie chemische Zusammensetzung, physikalische Phase, Dicke, Dichte, Härte und Schichtwiderstand wurden mit Hilfe von ex situ Messverfahren untersucht. Vor der Evaluierung neuartiger Nickelvorstufen ein Benchmark ALD-Prozess war vom Referenznickelvorläufer (Ni (AMD)) und Luft als Reaktionspartner entwickelt. Das Hauptziel der Entwicklung und Optimierung von solchen Benchmark-ALD-Prozess war es, Standard-Prozessparameter wie zweite Reaktionspartner Belichtungszeiten, Argonspülung Zeiten, gesamtprozessdruck, beginnend Abscheidungstemperatur und Gasströme zu extrahieren. Diese Standard-Prozessparameter mussten verwendet, um die Prozessentwicklung Aufgabe (das spart Vorläufer Verbrauch) zu verkürzen und die Sublimationstemperatur Optimierung für jede neuartige Vorstufe werden. Die ALD Verhalten wurde in Bezug auf die Wachstumsrate durch Variation des Nickelvorläuferbelichtungszeit, Vorläufer Temperatur und Niederschlagstemperatur überprüftNickel and nickel(II) oxide are widely used in advanced electronic devices . In microelectronic industry, nickel is used to form nickel silicide. The nickel mono-silicide (NiSi) has emerged as an excellent material of choice for source-drain contact applications below 45 nm node CMOS technology. As compared to other silicides used for the contact applications, NiSi is preferred because of its low resistivity, low contact resistance, relatively low formation temperature and low silicon consumption. Nickel is used in nickel-based rechargeable batteries and ferromagnetic random access memories (RAMs). Nickel(II) oxide is utilized as transistor gate-oxide and oxide in resistive RAMs. Atomic Layer Deposition (ALD) is a special type of Chemical Vapor Deposition (CVD) technique, that is used to deposit very smooth as well as homogeneous thin films with excellent conformality even at high aspect ratios. It is based on self-terminating sequential gas-solid reactions that allow a precise control of film thickness down to few Angstroms. In order to fabricate todays 3D electronic devices, technologies like ALD are required. In spite of huge number of practical applications of nickel and nickel(II) oxide, a few nickel precursors are available for thermal based ALD. Moreover, these precursors have resulted in poor film qualities and the process properties were also limited. Therefore in this master thesis, the properties of various novel nickel precursors had to be evaluated. All novel precursors are heteroleptic (different types of ligands) complexes and were specially designed by the manufacturer for thermal based ALD of pure nickel with H 2 as a co-reactant. In order to evaluate the novel precursors, a new methodology was designed to test small amounts (down to 2 g) of precursors in a very time efficient way. This methodology includes: TGA/DTA curve analyses of the precursors, thermal stability tests in which the precursors (< 0.1 g) were heated at elevated temperatures in a sealed environment for several hours, deposition experiments, and film characterizations. The depositions were monitored with the help of in situ quartz crystal microbalance, while application related film properties like chemical composition, physical phase, thickness, density, roughness and sheet resistance were investigated with the help of ex situ measurement techniques. Prior to the evaluation of novel nickel precursors, a benchmark ALD process was developed from the reference nickel precursor (Ni(amd)) and air as a co-reactant. The main goal of developing and optimizing such benchmark ALD process was to extract standard process parameters like second-reactant exposure times, Argon purge times, total process pressure, starting deposition temperature and gas flows. These standard process parameters had to be utilized to shorten the process development task (thus saving precursor consumption) and optimize the sublimation temperature for each novel precursor. The ALD behaviour was checked in terms of growth rate by varying the nickel precursor exposure time, precursor temperature and deposition temperature
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Ahmed, Mustafa M. Abdalla. "Alternating-Current Thin-Film Electroluminescent Device Characterization." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-233432.
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Jádrem této disertační práce bylo studovat optické a elektrické charakteristiky tenkovrstvých elektroluminiscenčních součástek řízených střídavým proudem (ACTFEL) a zejména vliv procesu stárnutí luminiforů na jejich optické a elektrické vlastnosti. Cílem této studie měl být příspěvek ke zvýšení celkové účinnosti luminoforů, vyjádřené pomocí jasu, účinnosti a stability. Vzhledem k tomu, že současnou dominantní technologií plochých obrazovek je LCD, musí se další alternativní technologie plošných displejů porovnávat s LCD. Výhodou ACTFEL displejů proti LCD je lepší rozlišení, větší teplotní rozsah činnosti, větší čtecí úhel, či možnost čtení při mnohem vyšší intenzitě pozadí. Na druhou stranu je jejich nevýhodou vyšší energetická náročnost, problém s odpovídající barevností tří základních barev a podstatně vyšší napětí nutné pro činnost displeje. K dosažení tohoto cíle jsme provedli optická, elektrická a optoelektrická měření ACTFEL struktur a ZnS:Mn luminoforů. Navíc jsme studovali vliv dotování vrstvy pomocí KCl na chování mikrostruktury a na elektroluminiscenční vlastnosti (zejména na jas a světelnou účinnost) ZnS:Mn luminoforů. Provedli jsme i některá, ne zcela obvyklá, měření ACTFEL součástek. Vypočítali jsme i rozptylový poměr nabitých barevných center a simulovali transportní charakteristiky v ACTFEL součástkách. Studovali jsme vliv stárnutí dvou typů ZnS:Mn luminoforů (s vrstvou napařenou či získanou pomocí epitaxe atomových vrstev) monitorováním závislostí svítivost-napětí (L-V), velikost vnitřního náboje - elektrické pole luminoforu (Q-Fp) a kapacitance-napětí (C-V) ve zvolených časových intervalech v průběhu stárnutí. Provedli jsme krátkodobá i dlouhodobá měření a pokusili jsme se i o vizualizaci struktury luminoforu se subvlnovým rozlišením pomocí optického rastrovacího mikroskopu pracujícího v blízkém poli (SNOM). Na praktickém případu zeleného Zn2GeO4:Mn (2% Mn) ACTFEL displeje, pracujícího při 50 Hz, jsme také studovali stabilitu svítivosti pomocí měření závislosti svítivosti na napětí (L-V) a světelné účinnosti na napětí (eta-V). Přitom byl zhodnocen význam těchto charakteristik. Nezanedbatelnou a neoddělitelnou součástí této práce je i její pedagogický aspekt. Předložený text by mohl být využit i jako učebnice pro studenty na mé univerzitě v Lybii.
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Snyder, Ryan Daniel. "Combinatorial Analysis of Thermoelectric Materials using Pulsed Laser Deposition." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1460037906.
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Jachalski, Sebastian [Verfasser], Barbara [Akademischer Betreuer] Wagner, Barbara [Akademischer Betreuer] Niethammer, and Dirk [Akademischer Betreuer] Peschka. "Derivation and analysis of lubrication models for two-layer thin-films / Sebastian Jachalski. Gutachter: Barbara Wagner ; Barbara Niethammer ; Dirk Peschka. Betreuer: Barbara Wagner." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1066162778/34.
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Lacinová, Eva. "Studium homogenity tenkých vrstev organických materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216436.
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This thesis deals with study homogeneity of thin organic layers using image analysis. The theoretical parts deal with preparation thin layers and some methods examining their surface, especially optical microscopy and profilometry. Optical microscope NIKON ECLIPSE E200, digital camera NIKON 5400 and computer was used for study homogeneity of organic layers by image analysis. Images of the organic layer and single electrodes, which were steamed on organic layer, were surveyed. Homogeneity of surfaces layers was assessed by errors related with common moments (roughness average, root mean square roughness, skewness, and kurtosis). Differences between single samples in connection with size their common moments and homogeneity are discussed at the close of this work.
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Boostandoost, Mahyar [Verfasser], and Christian [Akademischer Betreuer] Boit. "Signature of Photon Emission and Laser Stimulation for Failure Analysis of Semiconductor Devices with respect to Thin-Film Solar Cells / Mahyar Boostandoost. Betreuer: Christian Boit." Berlin : Technische Universität Berlin, 2013. http://d-nb.info/1065148127/34.
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Gifford, James Hart. "Optimization of the automated spray layer-by-layer technique for thin film deposition." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59883.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 82-83).
The operational parameters of the automated Spray-LbL technique for thin film deposition have been investigated in order to-identify their effects on film thickness and roughness. We use the automated Spray-LbL system developed at MIT by the Hammond lab to build 25 bilayer films of poly (ally amine hydrochloride) (PAH) and poly (acrylic acid) (PAA). Each of the 10 operational parameters of this system are explored individually to isolate each parameter's effect on film thickness and roughness. The parameter effects are analyzed for apparent trends to determine the parameters best suited for adjusting film thickness and roughness. The optimal parameters for thickness adjustment are polyelectrolyte solution concentration, polyelectrolyte spray time, spraying distance, air pressure and polyelectrolyte charge density. These parameters are independent of the type of species used to construct the film, and thus the trends should apply to any species used to construct thin films. The effect of each of the 10 operational parameters is examined in detail. While researching the parameter effects, polyelectrolyte interdiffusion in the films was observed. This interdiffusion is investigated using both the conventional dipped LbL and Spray-LbL deposition techniques. Interdiffusion is shown to be dependent on 3 factors, the charge density of the polyelectrolytes, the molecular weight of the polyelectrolytes, and the contact time between the polyelectrolyte solutions and the surface of the film. Interdiffusion is observed when the PAH is partially charged, the polyelectrolytes chains have a low molecular weight, and the contact time is sufficiently long enough to allow for interdiffusion. The significantly reduced contact time during the automated Spray-LbL process not only speeds up the film deposition time, but also significantly hinders the interdiffusion of PAH resulting in much thinner films than what is possible from dipping. Finally, the uniformity of the films produced using the automated Spray-LbL system is investigated. Films deposited on substrates greater than 1 in diameter area exhibit more than 20% variance in thickness. Adjustments were made to the setup of the system in an effort to expand this area of film thickness uniformity. However, it is determined that the design of this automated Spray-LbL system limits the film uniformity to an area of 1 in diameter.
by James Hart Gifford.
S.M.
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amini, manesh navid. "HEAT TRANSFER IN MULTI-LAYER ENERGETIC NANOFILM ON COMPOSITES SUBSTRATE." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3191.
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The main purpose of this work is the physical understanding and the numerical description of the reaction of the dense metastable intermolecular composition (MIC). Energy density of MIC is much higher than conventional energetic material; therefore, MIC finds more applications in the propellant and explosive system. The physical model includes the speed of propagation and rate of reaction, and the relationship between the layer thickness, heat rate, and length of the flame based on physical model. In Part I of this thesis, a one-dimensional model based on Weihs was developed for 20 pairs of a multi-layer of aluminum and copper oxide. This problem was solved using an assumed value of constant atomic diffusion in Arrhenius' equation to obtain the velocity of self- propagation. Using the maximum and minimum measured velocities in a similar configuration, the activation energy was computed and was found to be significantly different. When the velocity was used to obtain a linear temperature profile, the margin of error was significant as well. Therefore, this method was seen to have severe shortcomings. In Part II of this thesis, adiabatic unit cell of one layer of aluminum and copper oxide in an ideal reaction was considered. Temperature profile based on chemical heat generation and phase transformation of reactants has been calculated. This model confirmed the highest possible temperature during reaction of 2920 C ± 5% obtained in the literature, however, the model was unable to provide other important flame characteristics. In Part III, a two-dimensional model was developed introducing the flame at the interface. A black box theory has been used to simplify some of the characteristics of the flame, ignoring diffusion characteristics. Using this model, the length of flame was calculated using the measured value of the speed of propagation of the flame. Measuring some of the characteristics of the flame was the main goal of Part III of this thesis. Controllable environment was created for the multilayer thin film of aluminum and copper oxide to eliminate the number of effective variables that affect the speed of propagation. Transformable heat of reaction was used to control the speed of propagation. In addition, a MIC sample was designed and fabricated to measure the speed of propagation with an accuracy of 0.1 m/s. This measurement technique was used to measure the speed of propagation on variable substrate up to 65 m/s. The flame length was also calculated for different speeds of propagation over different substrates. The temperature distribution on the substrate was calculated numerically. Significant improvements have been made in Part III; however, this model does not provide concentration profiles. For future work, a more complete two-dimensional physical model will be developed for self-propagation reaction of multilayer thin film of aluminum and copper oxide based on thermal transport and atomic diffusion. This two-dimensional model includes the reaction rate, speed of propagation and the temperature profile. Since this model relies on a number of physical variables that are as yet unknown, further work is warranted in this area to carry out a thorough computational study.M.S.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering MSME
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Kim, Yunjo. "Two-dimensional material based layer transfer of thin film devices." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111747.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 40-42).
The semiconductor industry has mainly centered around silicon-based technology due to its associated cost advantage stemming from the abundance of the element and well-established fabrication infrastructures. However, there exists a plethora of compound semiconductors that offer unique electronic properties that can enable high performance devices superior to silicon for a wide range of device applications. Unfortunately, compound semiconductors industries have seen limited adoption in industries except in occasions where silicon-based technology cannot be used. This is mainly due to the rarity and high production costs associated with alternative semiconductor wafers. There have been many proposals that attempt to reduce the cost of production of these compound semiconductors by offering reusable wafers. In this scheme, the wafer is used as a platform to fabricate devices, the device layer is subsequently exfoliated from the wafer via a layer transfer allowing for the wafer to be re-used for continuous fabrication of thin-film devices. However, the layer transfer techniques that have been proposed so far often damages the wafer substrate, limiting their reusability and adding additional costs for surface refurbishment processes. This thesis proposes a novel layer transfer process, termed two-dimensional material based layer transfer (2DLT), which prepares thinfilm semiconductors by facile mechanical exfoliation to yield a clean wafer surface requiring minimal surface treatment. Moreover, this process can be applied to a wide range of material systems, suggesting a universal layer transfer process. The 2DLT process discussed in this work is enabled by a novel concept of semiconductor epitaxy, termed remote epitaxy. This thesis explores remote epitaxial growth of compound semiconductors on a graphene coated substrates and exfoliation of epitaxial films grown on graphene. Due to the atomic-thickness of graphene and weak van der Waals interaction on the surface of graphene, semiconductor adatoms on the surface of graphene can be made to register to the substrate for growth of single crystalline semiconductor films. In addition, the weak interactions at the interface of graphene provides a well-defined cleavage plane for facile mechanical exfoliation of the epitaxial film. This thesis investigates the conditions and mechanisms that facilitate remote epitaxy in order to identify the fabrication processes that enable 2DLT for compound semiconductors. The materials grown via remote epitaxy exhibited comparable properties to that of epitaxial films grown by conventional homoepitaxy, this has been demonstrated by fabrication of thin-film light emitting diodes (LEDs) and metal-semiconductor field-effect transistors (MESFETs), the results of which are presented in this work.
by Yunjo Kim.
S.M.
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Akintunde, Samuel Oluwafemi. "Formation of thin film of AB compound layer under irradiation." Thesis, University of Pretoria, 2016. http://hdl.handle.net/2263/60853.
Full textAbstract:
In this research study, we proposed a model that describes the formation of thin-film of an
AB compound layer at the interfaces of two immiscible solid layers A and B under the
influence of irradiation. However, we begin our study with a non-irradiation process where
we investigate the growth kinetics of an AB compound layer under the diffusion of one and
two kinds of species. This diffusion process takes place by means of one or two transport
mechanisms during an AB compound layer formation process. The results that follow from
this investigation reveal a complex growth kinetics of an AB compound layer under the
diffusion of two kinds of species by means of two transport mechanisms. However, the
complex growth behaviour transforms to simple linear-parabolic or parabolic growths
when only one kind of species diffuse by means of one transport mechanism.
In the irradiation aspect of the study, the A and B solid layers (bilayer system) are
considered to be bombarded by a beam of light and heavy energetic particles
independently under different considerations. We take into account two possibilities during
the irradiation of this bilayer system. Firstly, the majority of the kinetic energy of the
radiation particles is considered to be converted into heat energy which subsequently
results in the heating of the irradiated layers. We assume that the energy transferred from
the incident particles to the atoms of the irradiated materials during the course of
irradiation is less than their lattice threshold displacement energy. Thus, no defects are
generated during this process. The influence of heating that accompanies the irradiation
process is investigated to see if it could accelerate the growth of an AB compound layer at
the interfaces of the A and B layers. The second possibility is considered under the presupposition that the kinetic energy
transferred by the radiation particles is greater than the lattice threshold displacement
energy of the A and B layers; therefore, this process results in defects generation.
The contribution of the two basic point defects (i.e. interstitial and vacancy defects),
induced by irradiation, towards the growth of an AB compound layer is studied
independently.
The results that follow from this study show that the rate of growth of an AB compound
layer at the interfaces depends on the defect generation rate. The growth rate increases
proportionally with the defect generation rate. At high-temperature irradiation, the growth
rate depends strongly on both temperature and defect generation rate while at lowtemperature
irradiation it depends strongly only on defect generation rate. On the other
hand, the radiation heating makes no significant contribution towards the growth of an AB
compound layer at low temperature; this is because the dimensions of the A and B layers
that are considered in this study are in the order of a few tens of nanometers. Considering
the fact that the amount of energy deposited by the radiation particles increases with the
thickness of the irradiated layer, less energy is, therefore, deposited in the irradiated layers
under the thin film consideration. This reason makes radiation heating a less probable
process for an AB compound layer formation under the influence of irradiation.Thesis (PhD)--University of Pretoria, 2016.
Physics
PhD
Unrestricted
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York, Timothy Howard. "Pulsed laser deposition of electronic ceramics and analysis of the ablation plume." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362729.
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Schmidt, Marc J. J. "Pulsed laser ablation, deposition and processing of titanium doped Al₂O₃ and its analysis." Thesis, University of Hull, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272491.
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Bapanapalli, Srilatha. "Cds/cdte thin film solar cells with zinc stannate buffer layer." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001004.
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Moffett, Christina. "Characterization of Tellurium Back Contact Layer for CdTe Thin Film Devices." Thesis, Colorado State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10826197.
Full textAbstract:
Cadmium Telluride (CdTe) thin film photovoltaic technology has shown favorable progress due to inexpensive and efficient processing techniques. However, efficiencies have yet to reach the overall projected CdTe device efficiency, with the back contact being a main source of CdTe performance limitations. Tellurium (Te) applied as a back contact has led to significant increases in fill factor and an overall progress in device efficiency. Devices deposited with Te show significant improvement in uniformity, even without intentional Cu doping, when compared to devices without Te. In current - density measurements, Te shows stability even at low temperatures, which is indicative of a low barrier developed at the CdTe/Te interface. X-ray and ultra-violet photoelectron spectroscopy were carried out to examine the valence band offset at the CdTe/Te back contact interface. The valence band offset was shown to be highly dependent on the Te thickness and was largely affected by oxidation and contamination at the surface. Capacitance measurements were carried out to study the effect Te has on the absorber depletion width. Data indicate a decreased depletion width with Te applied at the back of thin film CdTe devices, which agrees with increased device performance. Te thickness was varied in all studies to understand the effect of application thickness on device performance and material characteristics. With a thicker Te layer leading to overall improvement in device performance and favorable device characteristics.
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Hegerová, Lucie. "Studium tloušťky tenkých vrstev organických materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216429.
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The diploma thesis deals with the determination of thickness and refractive index of thin organic films using image analysis. In the theoretical part there are described principles of the methods, which are used to prepare the films (spin coating, inkjet printing, vapour deposition), the characteristics of thin films, ways of finding out the thickness and refractive index of substances (weight methods, electric methods, method based on measurement of absorption coefficient of light, interference microscopy, ellipsometry) and also image analysis (harmonic and wavelet analysis). Interference microscope Epival - Interpako (Carl Zeiss Jena), digital camera Nikon Coolpix 5400 and computer were used for the determination of thickness and refractive index. The thicknesses of layers were set on the basis of interference images of edges and grooves – both from the side of the metal contact and the side of underlying glass. The refractive indices of thin layers were then set using the recorded figures. In the final part of the thesis there are discussed the results of interference images photographed along the full length of the aluminium contact which are used for measuring electrical characteristics of DPP structures. The produces are thicknesses and refractive indices of individual layers.
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Hu, Xiaobing. "Deposition and characterisation of bismuth layer-structured ferroelectric films." Thesis, University of Cambridge, 2006. https://www.repository.cam.ac.uk/handle/1810/194739.
Full textAbstract:
Bismuth layer-structured ferroelectrics have been recognised as promising film materials for ferroelectric random access memory application due to their excellent fatigue resistance and other electrical properties. This work deals with the deposition and characterisation of epitaxial and polycrystalline W-doped SrBi2Ta2O9 (SBT) and lanthanide-doped bismuth titanate (BiT) films. SBT and W-doped SBT films were fabricated by pulsed laser deposition (PLD) on platinised silicon substrates. The effects of fabrication temperature and W-doping level on film properties were studied. The crystallinity of SBTW films improved with increasing fabrication temperatures, resulting in enhanced ferroelectric properties and dielectric properties above the fabrication temperature of 750 °C. Dense ceramic samples of Nd- and Sm-doped BiT (BNdT and BSmT) were successfully fabricated for PLD targets by solid state processing. Highly epitaxially (001)-, (118)-, and(104)-oriented Nd-doped bismuth titanate (BNdT) films were grown by PLD on (001)-, (011)-,and (111)-oriented SrTiO3 (STO) single crystal substrates, respectively. A three-dimensional orientation relationship between films and substrates was derived as: BNdT(001)//STO(001),BNdT[ 110 ]//STO[100]. Films showed strong dependence of structural and ferroelectric properties on the crystal orientation. PLD-grown BSmT films on platinised silicon substrates were studied as a function of fabrication temperature, effects of Pt bottom layer orientation, Sm doping level, and LaNiO3 buffer layer. An alkoxide-salt chemical solution deposition (CSD) method was adopted to prepare the precursors for BSmT (BNdT) film fabrication. Precursors of Bi-Sm(Nd)-Ti which were stable for at least eight months in air ambient were successfully developed. In-situ FT-IR studies suggest that acetic acid serves as chelating agent to improve the homogeneity of the precursor solution by generating a dense and homogeneous Ti-O-Ti polymeric network. The electrical properties of the films fabricated in this study (dielectric and ferroelectric properties, leakage current characteristics and electrical fatigue properties), are comparable or superior to these previously reported for similar films developed by other techniques or with other doping elements. Low temperature electrical properties of BSmT films suggest that the films are very promising for extremely low temperature nonvolatile memory applications. The results of BNdT films annealed at different oxygen partial pressure (O2, air, N2) showed that oxygen ambience affected structural properties of the films by enhancing the growth of perovskite phase (phase formation), increasing grain size (grain growth), and assisting the growth of (117)-oriented grains (crystallographic orientations). Piezoresponse force microscopy (PFM) was adopted to characterise BSmT films. Domain structures were clearly observed in a PLD-grown BSmT film, which were closely related to the grain structures. Domain manipulation was carried out in a CSD-derived BSmT film, showing that the film can be nearly uniformly polarised, which can be used in nanoscale device fabrication. Clear hysteresis loops were measured by PFM, which was an important proof of ferroelectricity. Large spatial variations of piezoelectric hysteresis loops of a CSD-derived BSmT film were observed across the film surface. Effective electrostriction coefficient (Qeff) of a PLD-grown BSmT film was measured, showing that BSmT films had better piezoelectric properties (higher Qeff, higher dzz) than SBT films, un-doped BiT ceramics and films. It suggests that BSmT films are promising piezoelectric materials for MEMS use.
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Pillay, Sankara. "Development of a Dense Diffusion Barrier Layer for Thin Film Solar Cells." Thesis, Linköping University, Plasma and Coating Physics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-52365.
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Tantalum diffusion barrier coatings were investigated as a way to improve the conversion efficiency of CIGS (copper indium gallium diselenide) solar cells. Tantalum coatings were deposited upon silicon and stainless steel foil substrates using direct current magnetron sputtering (DcMS) and high power impulse magnetron sputtering (HiPIMS). The coatings were characterized using scanning electron microscopy (SEM). Cross-sectional scanning electron micrographs revealed that the HiPIMS coatings appeared denser than the DcMS coatings.
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Sarma, Kumaravinotha N. Sanmugaratna. "Barium strontium titanate thin film based multi-layer structures for microwave application." Thesis, London South Bank University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506714.
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Sommer, Oliver. "Ein Beitrag zur Untersuchung des Verhaltens dünner Flüssigkeitsfilme nahe gekrümmten Substratoberflächen." Doctoral thesis, Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-154946.
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In der vorliegenden Arbeit wurde das Verhalten dünner Flüssigkeitsfilme an gekrümmten Substratoberflächen durch experimentelle Beschichtungsversuche basierend auf der non-invasiven laserinduzierten Fluoreszenzmesstechnik und durch numerische Filmsimulationen mit Hilfe des Volume-of-Fluid Mehrphasenmodells untersucht. Besonderes Interesse galt dabei dem Finden optimaler Einflussgrößenkombinationen zur Reduzierung des Fettkanten-Effekts. In der hierfür durchgeführten Parameterstudie wurden sowohl Applikationsparameter wie der Kantenrundungsradius und die Applikationsschichtdicke als auch Stoffparameter der untersuchten Flüssigkeit wie die Viskosität und die Oberflächenspannung variiert. Neben qualitativen Beschreibungen der entstandenen Fettkantengestalten sind als Resultate auch Größen zur Quantifizierung der Fettkanten festgelegt worden und systematisch dargestellt. Es konnte nachgewiesen werden, dass ungünstige und geeignete Parameterkonfigurationen existieren, welche prägnante bzw. kaum auffällige Fettkanten erzeugen, insbesondere im Experiment. Über die dabei eingreifenden Mechanismen der zugrundeliegenden Strömungen wurden konkrete Hypothesen aufgestellt, auch um die resultierenden Proportionalitäten der Fettkantengrößen bezüglich der Einflussgrößen zu plausibilisieren. Weiterhin konnte eine Aussage über die Signifikanz der untersuchten Einflussgrößen getroffen werden. Abschließend wurde eine geeignete dimensionslose Kenngröße generiert, um den Fettkanten-Effekt parameterübergreifend beschreiben zu können, wodurch mittels der Ähnlichkeitstheorie auch eine gewisse Abschätzung des Fettkanten-Effekts ermöglicht wirdIn this study the behaviour of a thin liquid layer at a curved solid edge was examined by experimental coating investigations based on the laser-induced fluorescence technique and by numerical film simulations based on the Volume-of-Fluid multiphase flow model, respectively. The main motivation was to find optimal combinations of influencing quantities to reduce the fat-edge effect. Therefore a study of these quantities was performed, in which application parameters like edge radii of curvature and application layer thicknesses as well as determining liquid properties like viscosity and surface tension have been varied. Results are described qualitatively at corresponding fat-edge shapes and quantified by suitable fat-edge parameters, which had to be identified and selected. It could be shown that adverse and appropriate influencing parameter combinations exist, which generate conspicuous and less distinctive fat-edges, respectively - especially in laboratory experiments. The experimental findings and proportionalities regarding fat-edge shapes and dimensions are found to be physically plausible. Furthermore an order of significance of the influencing quantities established. Eventually, a dimensionless quantity was derived by dimensional analysis, which describes the fat-edge effect. Thus, the fat-edge effect has also been described by the application of similarity theory and the corresponding dimenionless number, respectively
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Severtson, Yuan C. "Stability analysis of thin film coating systems." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/17965.
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Parshall, Elaine Ruth 1962. "Phase-conjugate interferometry for thin film analysis." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/291358.
Full textAbstract:
A phase-conjugate interferometric method of thin film analysis obtains three independent parameters with which to determine a film's refractive index n, absorption coefficient kappa, and thickness d. Because dimensionless intensity ratios are used, this method is self-calibrating except for light source polarization and incident angle. The use of self-pumped phase-conjugate reflectors makes the interferometer self-aligning and results in infinite spacing of fringes of equal thickness. A single layer thin film sample was analyzed by this technique, and the results compared to those of ellipsometry.
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Craib, Glenn R. G. "Thin film structural determination and surface analysis." Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320771.
Full textAbstract:
A combined approach to the use of surface analysis techniques and X-ray diffraction has been introduced. In particular the development of the microstructure of UHV evaporated thin metallic films has been investigated with a view to clarifying influences on microstructure (particularly texture). This study has shown the wide range of experimental parameters which affect the final film structure, such as temperature, oblique incidence and substrate roughness. An automated energy dispersive X-ray diffractometer has been developed for the study of thin film texture. The required corrections for loss of intensity due to sample positioning have been developed and verified. Pole figures have been collected for erbium and nickel thin films (thickness 200-1200 nm) grown on molybdenum or glass substrates. Results for the erbium films show a substantial effect on the texture of the film, contributed by the temperature of the substrate during deposition. The texture varies from mixed fiber at low temperature, to a strong single fiber orientation at around 663 K, to mixed fiber at higher temperatures. The strong orientation at 663 K has been shown to vary from either (002) to (101) depending on as yet unknown experimental conditions. The effect of substrate roughness appears to be only in the degree of orientation and it does not affect the overall nature of the texture of the film. The texture of the nickel films shows a form of "granular epitaxy" at substrate temperatures above 300 K. The presence of tensile stress within one of these nickel thin film samples has been determined and is interpreted to give support to a proposed mode of granular epitaxy.
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Pottage, John Mark. "Analysis of thin-film photonic crystal microstructures." Thesis, University of Bath, 2003. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269994.
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Thota, Phanikrishna. "PATTERN EVALUATION FOR IN-PLANE DISPLACEMENT MEASUREMENT OF THIN FILMS." UKnowledge, 2003. http://uknowledge.uky.edu/gradschool_theses/307.
Full textAbstract:
The term Gossamer is used to describe ultra-lightweight spacecraft structures that solve the aerospace challenge of obtaining maximum performance while reducing the launch costs of the spacecraft. Gossamer structures are extremely compliant, which complicates control design and ground testing in full scale. One approach is to design and construct smaller test articles and verify their computational models experimentally, so that similar computational models can be used to predict the dynamic performance of full-scale structures. Though measurement of both in-plane and out-of-plane displacements is required to characterize the dynamic response of the surface of these structures, this thesis lays the groundwork for dynamic measurement of the in-plane component. The measurement of thin films must be performed using non-contacting sensors because any contacting sensor would change the dynamics of the structure. Moreover, the thin films dealt with in this work are coated with either gold or aluminum for special applications making the film optically smooth and therefore requiring a surface pattern. A Krypton Fluoride excimer laser system was selected to fabricate patterns on thin-film mirror test articles. Parameters required for pattern fabrication were investigated. Effects of the pattern on the thin-film dynamics were studied using finite element analysis. Photogrammetry was used to study the static in-plane displacement of the thin-film mirror. This was performed to determine the feasibility of the photogrammetric approach for future dynamic tests. It was concluded that photogrammetry could be used efficiently to quantify dynamic in-plane displacement with high-resolution cameras and sub-pixel target marking.
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Chen, Jiun-Wei, and 陳俊維. "Stress Analysis and Discussion of Multi-Layer Thin Film." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/56328969063610765829.
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碩士國立中興大學
應用數學系所
95
In this study, a simple mechanical model modified from the Stoney formula is presented for the calculation of residual stresses in thin films. The Stoney formula was derived based on the assumption of equi-biaxial residual stress in thin films. According to the experiments in previous researches, this assumption is not always true. In the present analysis, the residual stresses can be different in x-axis and y-axis; thus, a set of new formulas are derived instead of a single Stoney formula. Different thin film structures are investigated to demonstrate the differences between the results obtained by the Stoney formula and those by the present method. The proposed method should be more accurate than the Stoney formula in the stress calculation of such films.
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Liang, Yu-Chih, and 梁育誌. "The Thermal Conductivity Model Analysis of Thin-Film Material for Organic Emitting Layer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/zy5t55.
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碩士國立臺北科技大學
光電工程系研究所
98
The purpose of thesis research is to estimate the thermal conductivity of organic light-emitting thin-film material in Organic Light Emitting Diode (OLED) by means of solving two-dimensional heat transfer equation with simplified two-layer structure. The thermal conductivity of the organic light-emitting layer was obtained from fitting our parametric model to the experiment data acquired by our surface temperature measurement system. The parametric model developed in this study was first applied to single-layer Si and SiO2 for verifying its accuracy. The thermal conductivity of Si determined from our parametric model is between 130 and 147 W/m．℃, very close to acceptable reference. The thermal conductivity of ITO glass is also determined between 54 and 76 W/m．℃. The thermal conductivity of the organic light-emitting material (Alq3) is estimated between 0.28 and 0.29 W/m．℃, the same order with well-known organic compounds.
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Li, Fu-Hai, and 李富海. "Investigation on stability analysis for novel thin-film-transistors with a transparent a-IGZO channel layer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/21029337067288683098.
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碩士國立交通大學
光電工程學系
98
Amorphous oxide semiconductors (AOSs) are attracted much attention due to high mobility, low temperature deposition, flexible,transmission, and uniformity.It has been investigated of AOSs, such as ITO, IZO, TiO2, ZnO, In2O3, Ga2O3, IGO, a-IGZO,etc. Especially,the thin film transistors (TFTs) with a-IGZO thin film as active layer perform higher mobility and better reliability than conventional hydrogenated amorphous silicon TFT (a-Si: H TFT). In addition, the uniformity of a-IGZO TFT is also superior to Low Temperature Polycrystalline Silicon TFT (LTPS TFT). Therefore, the a-IGZO TFTs have the potential to replace a-Si: H TFT and LTPS TFT forming Active Matrix Organic Light Emitting Display (AMOLED). However, a-IGZO there are some inherent defect, such as sensitive to water and oxygen in ambient and light illumination thereby affect the device stability. The device reliability under GBS also has to be considered.In this thesis, we studied the interaction between surrounding oxygen and moisture with passivation-free a-IGZO thin film transistors.Time dependence threshold voltage variation in ambient of passivation-free a-IGZO TFT and reliability are investigated. Photo-reaction of a-IGZO TFT under UV-illumination is also investigated.From the experimental results, Adding N2 gas during a-IGZO deposition can improve the device stability and reliability under GBS. Finally we successfully investigated a novel bi-layer structure which insensitive to ambient air and improve storage and reliability issue and decreased photosensitive affects under ultraviolet(UV)-light illumination.
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Schaeffer, Luther Sterling. "Determination of norepinephrine in rat tissue by reversed-phase HPLC separation and amperometric detection using a boron doped nanocrystalline thin film electrode." Diss., 2006.
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Lin, Chao Jung, and 林朝榮. "Scanning Near Field Optical Microscopy Lithography Dot Processed Mode Analysis of Photoresist layer Coating Indium Thin Film." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/56307988414613459071.
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碩士國立臺灣科技大學
自動化及控制研究所
93
The objective of this research is to study an innovative lithography using the effect of thermal-induced super resolution, and to demonstrate that the technique can effectively reduce the exposed pit width on the photoresist layer. The technique makes use of a thin metallic mask layer deposited on the top of the photoresist layer. After illuminating with a focused laser beam, the mask layer opens an aperture in melting temperature area around the center of the laser spot. Because the aperture size is much smaller than the laser spot and the optical properties of solid mask layer are different from those of melting one, the intensity distribution of the transmission light would become narrower than that of the incident light and forms a below spot size. Can be found from the result of imitating, the range plating the indium membrane and reducing with the width of the mark not plating the indium can have been up to about 15%, but because simulation this processing depth too shallow, so FWHM to is it have trend of increase instead to reduce while being wide. This text to adjust probe bore and exposure time and power and development time and indium thin film thickness and energydensity above parameter. To observe this parameter of effect for pit width and FWHM. According to the simulation results, Indium thin film with a range of thickness 10 nm was evaporated on the photoresist layer as metallic mask layer. the pit width on the photoresist layer could be shrunk by more than 15% and FWHM could be shrunk 2.2%.
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Tsao, Shu-Wei, and 曹書瑋. "Electrical Analysis & Fabricated Investigation of Amorphous Active Layer Thin Film Transistor for Large Size Display Application." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/56670949870823913179.
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博士國立中山大學
光電工程學系研究所
99
In this dissertation, the electrical characteristics of generally used hydrogenated amorphous silicon (a-Si:H) TFTs in LCD and newly risen amorphous indium-gallium-zinc oxide (a-IGZO) TFTs were studied. For modern mobile display and large-size flat panel display application, the traditional thin-film transistor-liquid crystal display (TFT-LCD) technology confronts with a lot of challenges and problems. In general, flexible displays must exhibit some bending ability; however, bending applies mechanical strain to electronic circuits and affects device characteristics. Therefore, the electrical characteristics of a-Si:H TFTs fabricated on stainless steel foil substrates with uniaxial bending were investigated at different temperatures. Experimental results showed that the on-state current and threshold voltage degraded under outward bending. This is because outward bending will induce the increase of band tail states, affecting the transport mechanism at different temperatures. In addition, for practical operation, the electrical characteristics of a-Si:H TFTs under flat and bending situations after AC/DC stress at different temperatures were studied. It was found that high temperature and mechanical bending played important roles under AC stress. The dependence between the accumulated sum of bias rising and falling time and the threshold voltage shifts under AC stress was also observed. Because a-Si:H is a photosensitive material, the high intensity backlight illumination will degrade the performance of a-Si:H TFTs. Thus, the photo-leakage current of a-Si:H TFTs under illumination was investigated at different temperatures. Experimental results showed that a-Si:H TFTs exhibited a pool performance at lower temperatures. The indirect recombination rate and the parasitic resistance (Rp) are responsible for the different photo-leakage-current trends of a-Si:H TFTs under varied temperature operations. To investigate the photo-leakage current, the a-Si:H TFTs were exposed to ultraviolet (UV) light irradiation. It was found that the photo current of a-Si:H TFTs was reduced after UV light irradiation. The detail mechanisms on reducing/increasing photo-leakage current by UV light irradiation were discussed. Recently, the oxide-based semiconductor TFT, especially a-IGZO TFT, is considered as one of promising candidates for active matrix flat-panel display. However, the a-IGZO TFT exists significant electrical instability issue and manufacturing problems. As a consequence, we investigated the effect of hydrogen incorporation on a-IGZO TFTs to reduce interface states between active layer and insulator. Experimental results showed that the electrical characteristics of hydrogen-incorporated a-IGZO TFTs were improved. The threshold voltage shift (ΔVth) in hysteresis loop is suppressed from 4 V to 2 V due to the hydrogen-induced passivation of the interface trap states. Finally, we reported the effect of ambient environment on a-IGZO TFT instability. As a-IGZO TFTs were stored in atmosphere environment for 40 days, the transfer characteristics accompanying strange hump were observed during bias-stress. The hump phenomenon is attributed to the absorption of H2O molecule. Additionally, the sufficient electric field is also necessary to cause this anomalous transfer characteristic.
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Ali, Rizwaan. "On Modeling Of Constrained Piezoelectric Thin Films For Structural Health Monitoring." Thesis, 2009. http://hdl.handle.net/2005/635.
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The behaviour of a free-standing thin film differs from that of a film surface-bonded or embedded due to the boundary constraints. A general dearth of analytical models, in regard to prediction of the operational competence of a constrained Piezoelectric thin film, prevails. In conventional design of miniaturized thin film devices, several non classical effects, for instance the effect of boundary constraints, are not considered. To warrant the design and performance optimisation of thin film sensors, such effect must be taken into account in a forethoughtful manner. This thesis is an attempt to achieve such optimisation through modeling of thin films. The coupled problem of a film on a substrate is solved semi-analytically in theoretical cases; and by finite element analysis in realistic cases for damage identification in the host structure.
We first propose a two-dimensional analytical model of a constrained Piezoelectric thin film embedded in a host. Analytical expressions of capacitance and voltage across the electrodes are obtained by assuming first order shear deformation across the film thickness. The bonding layer between the film and the substrate, which is assumed to be an equivalent single layer including electrodes, insulation layer, adhesive layer etc., is modeled by taking into account its viscoelastic property. Residual stress is incorporated in the constitutive model through equivalent residual strain. Simulations on 10 m thick PVDF and 100 mPZT films are conducted. They illustrate the dependence of voltage response and capacitance on the applied stress, as well as on the residual stress. A maximum percentage variation in capacitance, as compared to the conventional estimate, is about 2% in a PVDF film and +75% to-65% in a PZT film for various combinations of tensile stresses applied at the ends of the film. Effect of residual stress is also exemplified via comparative response of a 1 m PZT film deposited on Pt/Ti/Si(0 0 1), with and without residual stress. For this case, an almost +50% increase in the voltage and an equivalent drop in the capacitance is observed.
Next, we look into the voltage response profile of this model by employing it as a sensor to identify a finite mode I and mode II sub-surface cracks in a finite size host. To model the embedded crack, additional perturbation functions in the displacement field due to linear elastic crack tips in an infinite solid under plane strain condition are introduced to accommodate the stress free conditions at its surfaces. The film model requires the interfacial displacement and traction conditions, which are obtained from the analysis of the host. The combined analysis of the film and crack models brings forth the voltage gradient along the film span as a direct indicator of the location of crack in the axial direction, whereas the voltage magnitude represents the size of the crack.
Following this analysis, a quasi three-dimensional(3-D) model of a Piezoelectric thin film surface-bonded to the host structure is proposed. With due consideration of restriction on the thickness of the film, here the model is based on a reduced 3-D continuum mechanics approach. The displacement field in the film is assumed to vary according to the third-order shear deformation theory; and the electrical and mechanical boundary conditions on the surfaces of the film are accommodated in a consistent manner. The formulation yields a governing inhomogeneous system of second-order Partial Differential Equations(PDEs), which is dependent on the displacement field at the film-host interface through force terms. Semi-analytical expressions of potential difference and capacitance are obtained. This system is solved numerically for two unknown rotations about X and Y axes of the film by finite element method. A maximum variation of about 2.5% is obtained in the capacitance of a 10 m PVDF film, as compared to its conventional estimate. The operational performance of this model is assessed in terms of its voltage response over the film area for various displacement fields. Conformation of this response to the input displacement field attests to its mathematical integrity.
Next, we ascertain the versatility of this model in its role as a sensor for Structural Health Monitoring. To deal with cracks in the host plate, finite size rectangular surfaces are introduced as crack faces. The film domain and the host domain are discretized with an a posteriori h-refinement strategy and compatible interfacial nodes at the film-host interface via finite element interpolation. The resulting coupled problem is solved by static finite element analysis. The nature of the voltage pattern over the film surface is peculiar to the mode of crack, and is a qualitative portrayal of its presence. To correlate the electric potential(voltage) –a distributed parameter – to the geometry and orientation of the crack, as well as to quantify it, electrostatic measures in terms of integrated potential difference and its spatial gradients on the film surface are proffered. The numerical implications of these measures are elicited through simulation results of various crack sizes in damaged and healthy hosts under identical conditions of stress and boundary. The pattern of these measures in a damaged host becomes oscillatory as compared to straight lines observed in a healthy host.
Furthermore, the reduced 3-D model is extended to perform dynamic analysis with the inclusion of inertial terms in the governing equilibrium equations. Subsequently, the acceleration terms appear in the governing inhomogeneous system of PDEs in the force terms. Finite element analyses of this extended film model on an isotropic beam with surface and sub-surface cracks, and on a composite plate with delamination, are then performed in the time domain. In all cases, an excellent conformation of the voltage profile at any point in the film domain to the velocity profile at the corresponding point in the film-host interface is observed. Again, to quantify the extent of damage in the host, we proffer electrical measures based on the Lpnorm, of second order, of the voltage and its directional derivatives. We exemplify the numerical implications of these measures in the time domain through sensitivity analysis in regard to the defected areas, and their region of occurrence relative to the film sensor. The response of the film model educes that the relatively flat curves after the first incident pulse in a healthy structure shoots off to a monotonic pattern in damaged hosts. The measures depict high degree of sensitivity in regard to the variation in the area of damage of any nature.
An apposition of the static and dynamic analyses is elaborated towards the end of this dissertation. It proves to be very insightful in the damage assessment of the host structure, for it shows the utility of the dynamic model to sense the location of the damage occurrence, whereas a more in-depth assessment on its nature and mode of the crack would demand a static analysis in its proximal regions.
To sum up, in light of these models and the proposed measures, this thesis establishes salient justifications pertaining to their pragmatic significance. We believe that these results represent an important contribution towards the ongoing research on understanding the role of boundary constraints in mechanically thin Piezoelectric films.
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Lin, Bing-Yi, and 林秉誼. "Fabrication and analysis for zinc oxide nanorod anti-reflection layer on Cd-free CuInGaSe2 thin film solar cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/51127764831704090774.
Full textAbstract:
碩士國立交通大學
照明與能源光電研究所
102
The Copper Indium Gallium Diselenide (CIGS) is the most promising material for solar cell application. Until now, the best conversion efficiency reaches 20.4% by EMPA, Swiss. However, the traditional buffer material is cadmium sulfide (CdS), the cadmium is toxic for environment. Thus the zinc sulfide (ZnS) was adopted for the alternative material for buffer layer in this thesis. On the other hand, the direct manner improved the conversion efficiency is application of anti-reflection layer. However, the traditional anti-reflection layer unable to reach broad-band anti-reflection due to the limitation of design. Thus, zinc oxide nanorod (ZnO NR) with graded refraction index was adopted for the anti-refleciton layer, and further improve the conversion efficiency of solar cell. For the ZnS buffer layer, we improved the deposition conditions consisted of initial point of deposition and mixed order of reactant and according to the growth mechanism in the chemical bath deposition, enhance the heterogeneous and suppress the homogeneous nucleation as possible to acquire the ZnS thin film with 100-nm-thick and 1.44-Zn/S ratio. For ZnO NR antireflection layer, we study the relationship between the height of ZnO NR and optical properties. We found the surface reflectance was reduced via the increase of height of ZnO NR but the transmittance was decreased accordingly. The absorption effect was proposed. After analyzing, the most promising period of ZnO NR growth for improvement of efficiency was between 8 and 14 minutes. Finally, we used ZnS as buffer layer and ZnO NR as anti-reflection layer for fabrication of CIGS solar cells. After analyzing the current-voltage characteristics, the CIGS solar cell with NR deposited for 11 minutes acquired the relative gains of conversion efficiency and short-circuit are 8.3% and 7.56%, respectively.
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Po-HsienSung and 宋柏賢. "Material Property Analysis of Amorphous Metallic Thin Films as Diffusion Barrier Layer." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/byd7gq.
Full textAbstract:
博士國立成功大學
機械工程學系
106
Copper has been widely used as an interconnect material due to its lower electrical resistivity and better thermomigration and electromigration resistance. However, as temperature and time increase during reflow process, Cu-Sn intermetallic compound gradually produced, excessive intermetallic compounds can result in poor reliability of solder bump. In the current , Ni as an barrier layer has been widely studied and industrially accepted in order to inhibit rapid copper diffusion in interconnect structures. The proportion of intermetallic compound ratio in the solder bumps will be increased due to the shrinking of package devices. In addition, the current density in the solder bump needs to be increased, under such high current density, the thermomigrtion and electromigration in the solder bump becomes a serious reliability issue . Amorphous metallic films have been considered to be the most effective barriers layer for Cu metallization due to the absence of grain boundaries and immiscibility with copper. The time and cost required for nano-scale experimant may be exceedingly large, and for this reason molecular dynamics have been used to analyze the material properties of CuAg and ZrCuNiAl amorphous metal films in this study, including the glass transition process of amorphous metal films, the effect of composition ratio and quenching rate on the internal microstructure of amorphous metal films, diffusion Properties and the strength of the interface between polycrystalline and amorphous thin film. The results show for CuAg alloys, Cu20Ag80 present 50% amorphous at quenching rate of 25 K/ps, but Cu40Ag60 and Cu60Ag40 present more than 95% of the amorphous at quenching rate Between 0.25 K/ps and 25 K/ps, which indicates that it has a good glass forming ability. For the diffusion side, the better barrier performance with heigher of the amorphous ratio. For the interfacial tensile test, the ZrCuNiAl alloys which consist of four elements mixed together, almost no strain occurs during tensile, and the initial void will be generated at polycrystal Cu, which indicates the strength of ZrCuNiAl/Cu interface is greater than polycrystal Cu. From the experiment, the sample with the Zr53Cu30Ni9Al8 TFMG barrier layer, almost no IMC can be observed even after aging at 125°C for 500 hr, which indicates that it has a good barrier effect.
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Yan, Shih-Ping, and 顏士評. "Electrical Characteristic Analysis of A-IGZO Thin-Film-Transistors with Passivation Layers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/b54hnq.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
100
Amorphous oxide semiconductors and wide-band-gap transparent are promising functional components for next-generation devices. This dissertation describes the fabrication and characterization of optoelectronic devices (transistors) with a-InGaZnO. In this study, fabricating SiO2 gate insulator for a-InGaZnO thin-film transistors on glass, we fabricate bottom-gate structure using a-InGaZnO film as an active channel layer and SiO2 as gate insulator ans ITO as the gate, source, and drain electrode grown by using rf-sputtering. However, a-IGZO transistors have some inherent defect, in this study, research a-InGaZnO thin-film transistors with passivation layers as sensitive to water and oxygen thereby affect the device stability and time dependence threshold voltage variation in ambient of passivation layer and reliability are investigated. First use the different thickness of the passivation layer to observe the characteristic changes, and then investigate the annealing characteristics of change.
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Li, Guo-Hui, and 李國輝. "Fabrication and Analysis of Mn-doped（BaxSr1-x）TiO3 Thin Film Used as the Insulating Layer for MIS Structure Capacitors." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/76679742339064362011.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
95
During developing semiconductor process, the IC must scaling size for enchance IC velocity and affect .The SiO2 insulator layer will scale to narosize . Because the leakeage current becomes large , IC mobilty decreases and current drive is not enough to push next cuircuit. The insulator layer uses high k to reduce scaling size current problem.The deposited method in thesis was adopted the R.F. supptering .The thesis discusses five diffrence type of BST thin films deposition. It are variable deposited temperture、variable deposited power、variable OMR、variable dopped manganese on BST thin film、and anneling temperture of the BST thin film. In the only BST thin film discussion, the bast electric charateristic is OMR（Ar：O2=6：6）that I measure ； on the contrary , although in the fewer O2 concentration was deposted vary fast , the BST thin film which dielectric content and leakage currence was poor . Dopping Mn in the thin film was found when it increases Mn to decrease rms and enhace deposition quality . So we discussed dopping Mn on thin film and oxygen vacancies , relation. Afrer dopping 1wt% Mn ,and leakage current was 8.85E-8 A/cm2,and used annealing to get the best leakage current 6.23E-8 A/cm2.
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Huang, An Di, and 黃安笛. "Study on Annealing Effect and Reliability Analysis of Thin Film Transistors with a Transparent Amorphous Indium Gallium Zinc Oxide Channel Layer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/26056037022401804481.
Full textAbstract:
碩士明新科技大學
電子工程研究所
98
In this research, we successfully fabricated high performance transparent indium gallium zinc oxide (InGaZnO), which is the most promising material for channel layer of thin film transistors (TFTs) of next generation display. Different from prior literatures which IGZO thin films were deposited by radio frequency sputtering (RF sputtering), IGZO thin films were deposited by DC sputtering system in this study to be compatible with the Liquid Crystal Display industry. The un-doped IGZO thin film transistor with staggered structure were deposited by DC sputtering system. The oxygen effect of electrical properties of IGZO films were studied by changing the oxygen flow during deposition process. The annealing effect was also discussed to clarify the impact of verious annealing temperature on electrical chracteristics of IGZO thin film transistors. We successfully fabricated the device with high performance by 450℃ annealing process. The mobility is as high as 7.85 cm2/Vs, sub-threshold swing is 0.27 V/decade, and threshold voltage is 0.72V. Several material analysis techniques, such as X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Atomic Force Microcopy (AFM), etc. were utilized to discuss the crystallization, grain size, and surface morphology of IGZO thin films. Electrical characteristics and conduction mechanisms of IGZO TFT devices were also investigated by I-V characteristic analysis.
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Xie, Ming-Hsun, and 謝明勳. "The characteristic analysis on the buffer layer of CIS thin film solar cell by Chemical Bath Deposition and Sputtering Deposition methods." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12277085548195744246.
Full textAbstract:
碩士崑山科技大學
光電工程研究所
98
In this thesis, the CdS buffer layer of CuInSe2 (CIS) thin film solar cell is fabricated by Chemial Bath Deposition （CBD）and Sputtering Deposition (SD) methods, respectively. And there are two kinds of CBD methods, they are Co-melting CBD method and Separate-melting CBD method, respectively. The Co-melting CBD solution is completed with ammonium sulfate, cadmium sulfate, thiourea and ammonia melting together into 400 ml deionized water. For the Separate-melting CBD solution, firstly ammonium sulfate and mole cadmium sulfate melting separately into 50 ml deionized water, respectively; and thiourea and ammonia are mixed together; then the above three solutions are poured into 300 ml deionized water to become the final solution. The reason of adopting the CdS thin film as the buffer layer of CIS thin film solar cell is that the CdS can play as energy gap buffer and reduce the band-offset between CIS absorbing layer and the Transparent Conductive Oxide (TCO) layer. The CdS thin films are generated by above two kinds of CBD methods in situation of atmosphere. And the CdS thin film generated by SD method is in situation of 3.7 mtorr vacuum pressure. In order to analyze the characteristics of the CdS thin films conveniently, the CdS thin films are firstly fabricated on Soda-lime, and the final found optimal CdS thin film is fabricated on the CIS/Mo/Soda-lime. Then the p-n diode characteristic of the CdS/CIS/Mo/Soda-lime is measured by four-point probe. The CdS thin film obtained by SD method is adopted RF power with range from 200 W to 500W. It is found by analysis that 500 W is the optimal RF power; more uniform thickness of CdS thin film can be obtained and its thickness is easier to control. And the CdS thin films are fabricated by the above two kinds of CBD methods through various combinations of time interval from 20 to 60 minutes and temperature range from 70 ℃ to 85 ℃. It is found that the 80 ℃ and 60 minutes is the optimal combination; the smoother surface and more uniform thickness of Separate-melting CBD CdS thin film can be obtained. And it is found from optical characteristic analysis that in situation of emitted light wave length 500nm, the transmittance of the Separate-melting CBD CdS thin film is 61%, and it is better than that of SD CdS thin film with 56%. Meanwhile, the band gap of Separate-melting CBD CdS thin film is close to theoretical value of 2.4 eV. Then the Separate-melting CBD and SD CdS thin films are stacked on the CuInSe2/Mo/Soda-lime, respectively. It is shown that the p-n diode characteristic curve of the Separate-melting CBD CdS/CIS/Mo/Soda-lime is better than that of the SD CdS/CIS/Mo/Soda-lime. Thus, it is proved that the Separate-melting CBD method can obtained a better CdS thin film.
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HSIEN, CHAN CHIEH, and 詹傑顯. "A study of micro-morphous silicon thin film solar cell light reflect layer improve and physics transfer efficiency analysis of characteristic." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/01221585692480140755.
Full textAbstract:
碩士國立高雄應用科技大學
電機工程系
99
The thesis presents improve micro-morphous light reflect layer effect and transfer efficiency of physics. Use white reflect layer with screen printer technology make light all reflect layer to best conditions and increase photo voltage transfer area purpose. The utilization ratio, through reflecting the number of times of printing of layer whitely then increasing the reflection result again of the light. Through repeat reflect layer print ,produce same material gap, make different reflect rate. Discuss snell’s optics refract theorem, make reflect layer of texture structure, increase Isc(A) and photo voltage efficiency P.mpp(W). Utilize using the area the most largely of the mould group of photo voltage effectively, increase the photo voltage and react on storey and change voluntarily, and then narrow the space of the invalid district of photo voltage by every Cell 400um to 200um range, let the each laser interval optimization improve the conversion efficiency on reaching the physical property. This thesis reflects the mechanism and analyses that explains to the light of the solar cell, carry on light reflect with actual sun mould group and simulation thickness of layer and parameter analyses prove trend picture is it compare to make, include P.mpp (W) , Isc (A) , Voc (V) , Rs (Ω) , Rsh (Ω) ,Reduction course of improving the conversion efficiency and analyzing the invalid district of photo voltage mainly on the physical property. It is expected benefit that can obtain for is it short current Isc(A) to raise. The utilization ratio, to the photo voltage transfer efficiency P.mpp(W) of the mould group again of and the light Very obvious improvement, it is estimated every Cell increases by area of generating electricity 1.4%, the whole area reflects efficiency and estimates that can be improved by 1%.
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Chao, Shih-Chun, and 趙士鈞. "Stress Analysis and Applications of Titanium Oxide Thin Films Grown by Atomic Layer Deposition." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/26468249765209831417.
Full textAbstract:
碩士國立臺灣大學
材料科學與工程學研究所
102
In this study, we investigate the properties of TiO2 thin films grown by atomic layer deposition method (ALD) and apply them to the resistive random access memory devices (ReRAM). For the application in the ReRAM devices, various characterization methods, such as transmission electron microscopy (TEM), X-ray photoelectron microscopy (XPS), are used to analyze the properties of TiO&;#172;2 thin films. Based on the experimental results, it shows that TiO2 films with different properties, such as the crystal structure, the chemical composition and the concentration of oxygen vacancies, can be grown by tuning the growth parameters. Besides, because some fractures in the polycrystalline TiO2 films are observed in the cross-sectional TEM images, it proves the existence of the residual stress. In this study, TEM techniques are used to measure the residual stress in thin films. According to the experimental results, we infer the residual stress is thermal stress. During the growth, amorphous TiO2 films are deposited on the substrates, and crystallize to release the thermal strain energy at the critical thickness in the cooling process. In the ReRAM devices, amorphous TiO2 thin films are used to reduce the concentration of the defects; at the same time, the thickness of thin films is reduced to avoid the high accumulated strain energy and the fracture problems. Based on these experimental results, we successfully apply ALD-grown TiO2 films to the ReRAM devices and investigate the I-V characteristics of the two different device structures, Pt/TiO2/Pt and FTO/TiO2/ITO. It shows that the stability of the devices with the Pt/TiO2/Pt structure is not good enough because its resistive switching mechanism. On the other hand, the stability and the operating characteristics are improved significantly using the conducting metal oxides, such as the FTO and ITO thin films, as electrodes. Key words: Titanium oxide, Atomic layer deposition, Transmission electron microscopy, Strain analysis, Resistive random access memory.
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HSUEH, NAI-KUEI, and 薛乃魁. "Deposition and Analysis of TiO2/Al2O3 Multi-Layer Thin Films for Applications in Distributed Bragg Reflectors." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4p872y.
Full textAbstract:
碩士國立高雄大學
化學工程及材料工程學系碩士班
105
In this study, multi-layers structure of TiO2/Al2O3 was fabricated by Bragg reflector principle. There were two kinds of deposition order (TA、AT), the parameters of TA in deposition order of Glass│TiO2│Al2O3, the parameters of AT in deposition order of Glass│Al2O3│TiO2. The microstructures, crystal structures, surface roughness and optical properties of multilayer films were investigated by scanning electron microscopy, X-ray diffraction analyzer and atomic force microscopy and Film characteristics analyzer. The purpose was to analyze the structure of multilayer films in the range of visible light blue light reflectance effect. In this study, the single layer of TiO2 and Al2O3 thin films were deposited onto glass substrates by electron beam evaporation method. Experimental parameters is electron beam accelerating voltage was 4 kv, evaporation rate was 1Å/sec, working pressure of 4×10-5torr, the oxygen flux was 6 sccm and the substrate was heated at 300℃. The refractive index of the TiO2 thin film deposited by electron beam evaporation was 2.2, and the refractive index of the Al2O3 thin film deposited by electron beam evaporation was 1.74, which was consistent with our calculation in the 1/4 optical wavelength thickness formula. After confirming the process parameters, multi-layers structure of TiO2/Al2O3 thin films were deposited onto glass substrates by electron beam evaporation method , and deposited 1 pair to 6 pairs of multilayer films. The SEM analysis results showed that the TiO2/Al2O3 multilayer film structure has been successfully deposited onto glass substrates by electron beam evaporation method. The X-ray diffraction patterns showed that multi-layers structure of TiO2/Al2O3 thin films both groups are amorphous structure. The AFM analysis showed that although the number of films increased, the surface roughness slightly increased, which proved that the surface of the multilayer film has good quality. The optical properties analysis showed that multi-layer structure of 6 pairs in TA and AT stacking order exhibit the optical reflectance of 90% and 95% in the visible blue light range. We also used three kinds of LED light (blue, green, red) irradiated on uncoated glass substrates and the samples of two stacking orders for support this multilayer structure with high reflection and very low penetration effect in the visible light blue range.
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Hsiao, Chih-ping, and 蕭致平. "Investigation of Ge thin film analysis process during excimer laser annealing using in-situ time-resolved optical reflection and transmission measurement and Si thin films recrystallization mechanism." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/d6gm85.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
95
An in-situ real-time time-resolved optical reflectivity and transmissi vity (TRORT) monitoring system combining two CW He-Ne laser, a fast digital oscilloscope and three photodiodes is developed for monitoring the melt-phase duration and examine the melting and crystallization behavior during XeF excimer laser annealing(ELA) and use Transmission Electron Microscopy(TEM) to analyze crystallization mechanisms of poly-Si in this study. We use ELA to crystallize amorphous germanium on difference absorption coefficient film(SiON).The grain size of germanium will increase to 10 μm. The grain size measurement of difference absorption coefficient film is compared and the germanium is different in melt-phase duration.The grain size is judged must match in melt-phase duration and absorption coefficient of SiON films. Using TRORT system can examine the melting and crystallization behavior, and measure the melt-phase duration. This technique provides a simple approach for fabrication large-grained poly-Ge during ELA and enhances the high yield during in-line large area flat panel displays fabrication.
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Tsai, Hung-Ching, and 蔡泓璟. "Multi-objective Optimization of Laser Scribing for Metal Thin Film on TFT-LCDs Using Grey Relation Analysis." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/rr77g2.
Full textAbstract:
碩士國立臺北科技大學
機電整合研究所
99
Traditional manufacturing of the thin film transistor liquid crystal display (TFT-LCD) uses wet process equipments, hence producing large amounts of toxic liquid waste. This study presents a method of using dry equipment with high-precision laser isolation engraving on the LCD glass panel for non-pollution etching process. This paper will use 532nm wavelength green laser as the processing platform for insulation experiments, and aim to achieve parameter optimization of laser isolation process on the glass metal thin film through grey relational theory. In this study of laser isolation process, the two main targets are that the glass substrate not melted and successful metal film insulation. Under the requirements of scribing the metal film with a certain groove width and minimizing the heat affected zone, we plan to integrate the laser system operating parameters to achieve the targets. Therefore, the laser parameter selections are the key elements for the isolation process. These key parameters include laser focusing position, average laser power and Q-switch frequency. Using the experimental result and the grey theory analysis, we illustrate the validity of applying the grey theory to laser isolation process. This paper verifies the application of 532nm laser to the glass panel metal film with an appropriate combination of control parameters that can obtain excellent processing performance.
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Dawood, Mahmoud. "Space and time characterization of laser-induced plasmas for applications in chemical analysis and thin film deposition." Thèse, 2014. http://hdl.handle.net/1866/12347.
Full textAbstract:
Après des décennies de développement, l'ablation laser est devenue une technique importante pour un grand nombre d'applications telles que le dépôt de couches minces, la synthèse de nanoparticules, le micro-usinage, l’analyse chimique, etc. Des études expérimentales ainsi que théoriques ont été menées pour comprendre les mécanismes physiques fondamentaux mis en jeu pendant l'ablation et pour déterminer l’effet de la longueur d'onde, de la durée d'impulsion, de la nature de gaz ambiant et du matériau de la cible.
La présente thèse décrit et examine l'importance relative des mécanismes physiques qui influencent les caractéristiques des plasmas d’aluminium induits par laser. Le cadre général de cette recherche forme une étude approfondie de l'interaction entre la dynamique de la plume-plasma et l’atmosphère gazeuse dans laquelle elle se développe. Ceci a été réalisé par imagerie résolue temporellement et spatialement de la plume du plasma en termes d'intensité spectrale, de densité électronique et de température d'excitation dans différentes atmosphères de gaz inertes tel que l’Ar et l’He et réactifs tel que le N2 et ce à des pressions s’étendant de 10‾7 Torr (vide) jusqu’à 760 Torr (pression atmosphérique).
Nos résultats montrent que l'intensité d'émission de plasma dépend généralement de la nature de gaz et qu’elle est fortement affectée par sa pression. En outre, pour un délai temporel donné par rapport à l'impulsion laser, la densité électronique ainsi que la température augmentent avec la pression de gaz, ce qui peut être attribué au confinement inertiel du plasma. De plus, on observe que la densité électronique est maximale à proximité de la surface de la cible où le laser est focalisé et qu’elle diminue en s’éloignant (axialement et radialement) de cette position. Malgré la variation axiale importante de la température le long du plasma, on trouve que sa variation radiale est négligeable. La densité électronique et la température ont été trouvées maximales lorsque le gaz est de l’argon et minimales pour l’hélium, tandis que les valeurs sont intermédiaires dans le cas de l’azote. Ceci tient surtout aux propriétés physiques et chimiques du gaz telles que la masse des espèces, leur énergie d'excitation et d'ionisation, la conductivité thermique et la réactivité chimique.
L'expansion de la plume du plasma a été étudiée par imagerie résolue spatio-temporellement. Les résultats montrent que la nature de gaz n’affecte pas la dynamique de la plume pour des pressions inférieures à 20 Torr et pour un délai temporel inférieur à 200 ns. Cependant, pour des pressions supérieures à 20 Torr, l'effet de la nature du gaz devient important et la plume la plus courte est obtenue lorsque la masse des espèces du gaz est élevée et lorsque sa conductivité thermique est relativement faible. Ces résultats sont confirmés par la mesure de temps de vol de l’ion Al+ émettant à 281,6 nm. D’autre part, on trouve que la vitesse de propagation des ions d’aluminium est bien définie juste après l’ablation et près de la surface de la cible. Toutefois, pour un délai temporel important, les ions, en traversant la plume, se thermalisent grâce aux collisions avec les espèces du plasma et du gaz.After decades of development, laser ablation has become an important technique for a large number of applications such as thin film deposition, nanoparticle synthesis, micromachining, chemical analysis, etc. Experimental and theoretical studies have been conducted to understand the physical mechanisms of the laser ablation processes and their dependence on the laser wavelength, pulse duration, ambient gas and target material. The present dissertation describes and investigates the relative importance of the physical mechanisms influencing the characteristics of aluminum laser-induced plasmas. The general scope of this research encompasses a thorough study of the interplay between the plasma plume dynamics and the ambient gas in which they expand. This is achieved by imaging and analyzing the temporal and spatial evolution the plume in terms of spectral intensity, electron density and excitation temperature within various environments extending from vacuum (10‾7 Torr) to atmospheric pressure (760 Torr), in an inert gas like Ar and He, as well as in a chemically active gas like N2. Our results show that the plasma emission intensity generally differs with the nature of the ambient gas and it is strongly affected by its pressure. In addition, for a given time delay after the laser pulse, both electron density and plasma temperature increase with the ambient gas pressure, which is attributed to plasma confinement. Moreover, the highest electron density is observed close to the target surface, where the laser is focused and it decreases by moving away (radially and axially) from this position. In contrast with the significant axial variation of plasma temperature, there is no large variation in the radial direction. Furthermore, argon was found to produce the highest plasma density and temperature, and helium the lowest, while nitrogen yields intermediate values. This is mainly due to their physical and chemical properties such as the mass, the excitation and ionization levels, the thermal conductivity and the chemical reactivity. The expansion of the plasma plume is studied by time- and space-resolved imaging. The results show that the ambient gas does not appreciably affect plume dynamics as long as the gas pressure remains below 20 Torr and the time delay below 200 ns. However, for pressures higher than 20 Torr, the effect of the ambient gas becomes important and the shorter plasma plume length corresponds to the highest gas mass species and the lowest thermal conductivity. These results are confirmed by Time-Of-Flight (TOF) measurements of Al+ line emitted at 281.6 nm. Moreover, the velocity of aluminum ions is well defined at the earliest time and close to the target surface. However, at later times, the ions travel through the plume and become thermalized through collisions with plasma species and with surrounding ambient gas.