Dissertations / Theses: 'Solid thin film metals'

1

Duff, Daniel Gordon. "Colloidal solutions and thin films of metals." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333275.

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2

Zaidi, Syed Zulfiqar Ali. "Electrical and optical properties of some metal/SiOâ†x thin film systems." Thesis, Brunel University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307488.

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3

Matz, Dallas Lee. "Raman Spectroscopic Investigations of the Interfacial Chemistry of Solid-State Organic Thin Films with Vapor Deposited Metals for Organic Photovoltaics." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/268594.

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This dissertation is focused on the elucidation of the reaction chemistry that governs the low work function metal/organic interface found in organic photovoltaics (OPVs). To this end Raman spectroscopy was used in ultra-high vacuum to study Ag, Mg, Ca, and Al metal vapor deposition on pyridine, C₆₀, and graphene. In an effort to understand the interfacial reaction chemistry of complex organic molecules with metal an approach of systematic deconstruction is used where by small molecules, in this case pyridine can be used to gain insight into the chemistry of various chemical functionalities with minimal spectral complication. In the Ag/pyridine system no reaction was observed and the integrity of the film was preserved with spectral enhancement being the only result. This enhancement is achieved via a weak Ag--N bonding interaction. For the other three metals (Mg, Ca, and Al) a great deal of fascinating reaction chemistry can be observed initiated in each case by metal-to-organic electron transfer resulting in the formation of pyridyl radical anions. Once radicals are formed the reaction pathways for each metal diverge resulting in different specific reaction products. In the case of Mg the pyridyl radicals undergo reductive dimerization and yield 4,4'-bipyridine. For Ca the pyridyl radicals follow two pathways either losing a hydride to form the diradical pyridyne or through a pathway of ring opening degrade into amorphous carbon. These results highlight the vast differences possible for reaction chemistry between metals and organics even for simple molecules. Buckminsterfullerene (C₆₀) and fullerene derivatives are ubiquitous to the field of OPVs, thus an understanding of their metal/organic interfacial chemistry is of critical importance to unlocking the full potential of devices. In a similar manner to what can be observed for Ag/pyridine systems the Ag/C₆₀ system shows little more than surface enhancement effects due to a lack of any substantial reactivity and Mg, Ca, and Al exhibit metal-to-organic charge transfer forming C60 anion radicals. These anion radical react to form an as of yet unidentified reaction product in the case of all three reactive metals and in the case of Al these reaction products further degrade forming amorphous carbon. The understanding of this chemistry can be directly correlated to device data found in the literature and provides insight into the formation of interfacial gape states at the metal/organic interface of OPVs. Due to its unique electrical properties and high degree of mechanical stability graphene is starting to play a significant role in the development of OPVs. Because graphene is being used in contact with vapor deposited metal it is of relevance to understand the chemistry that occurs at this interface. While deposition of Ag onto graphene again shows no reaction and only enhancement the enhancement leads to the identification of unique defects in the graphene lattice namely carbon vacancies and C--C bond rotations which lead to Stone-Wales defects which are likely a result of the graphene growth method. Mg, Ca, and Al show strong evidence for n-type doping of electrons into the graphene film due to their work functions being lower than graphene. This data highlight the stability of graphene showing that even though it undergoes a similar metal-to-organic electron transfer as seen with C₆₀ and pyridine there is no further compromise of the films molecular structure.

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4

RUSSAT, JEAN. "Contribution a l'etude, par spectroscopie de photoelectrons, d'interfaces polymere-metal : application au cas de l'acide polyamique et du polyimide." Paris 7, 1987. http://www.theses.fr/1987PA077237.

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5

Guttman, Jeremy. "Polymer-based Tunnel Diodes Fabricated using Ultra-thin, ALD Deposited, Interfacial Films." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469125487.

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6

Triana, Carlos A. "Atomic short-range order, optical and electronic properties of amorphous transition metal oxides : An experimental and theoretical study of amorphous titanium aTiO2 and tungsten aWO3 solid thin-film oxides." Doctoral thesis, Uppsala universitet, Fasta tillståndets fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-318193.

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Amorphous transition metal oxides [aTMOs], have emerged as innovative functional materials for wide-ranging electronic, optical and energy-related applications. However, no systematic and broadly applicable method exists to assess their atomic-scale correlations, and since the optical and electronic processes are local structure-dependent, still there are not well-stablished mechanisms that suitably explain the physical properties of aTMOs. This thesis presents experimental and theoretical studies of the atomic short-range order, optical and electronic properties, and state-defects induced by Li+-ion-intercalation and oxygen-vacancies in amorphous titanium aTiO2 and tungsten aWO3 thin-film oxides. Those properties play a key role for application in high energy-density Li+-ion batteries and in switchable dynamical modulation of solar-irradiation transmittance for energy efficient "smart windows", where the disorder-dependent Li+-ion-intercalation and oxygen-vacancy-induced defect-states influence charge-carrier transfer mechanisms. After introducing the scope of this thesis, the fundamental theoretical concepts describing the experimental findings on amorphous solids are reviewed. Thereafter, a comprehensive analysis on the optical absorption phenomena experimentally observed in oxygen-deficient and Li+-ion-intercalated aLixTiO2−y and aLixWO3−y thin-films and a discussion on the electrochromic properties are presented. The optical absorption is described in the framework of the small polaron absorption model. Finally, a state-of-the-art systematic procedure involving theory and experiment in a self-consistent computational framework is implemented to unveil the atomic-scale structure of aTiO2 and aWO3, and its role for the electronic properties. The procedure is based in Reverse Monte Carlo [RMC] and Finite Difference Method [FDM] simulations of X-ray-Absorption spectra to construct a disordered theoretical model having the same bonding and coordination distribution as the experimental system. Ab-initio molecular dynamics simulations and density functional theory are then used to assess defect-states induced by Li+-ion-intercalation and oxygen-vacancies in aTiO2 and aWO3 oxides. The schemes introduced in this study offer a consistent route to experimentally and theoretically assess the role of the atomic-scale structure on the optical and electronic properties of aTiO2 and aWO3 and could be extended to the study of other aTMOs. The final results provide crucial insight towards the understanding of optical and electronic mechanisms where disorder-dependent ion-intercalation and oxygen-vacancy-induced localized defect-states influence charge transfer mechanisms of crucial importance for wide ranging optical and energy-related application of aTiO2 and aWO3 oxides.

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7

Ross, Caroline Anne. "Electromigration in thin metal films." Thesis, University of Cambridge, 1989. https://www.repository.cam.ac.uk/handle/1810/250938.

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8

Maaroof, Abbas I. "Optical and electrical properties of ultra thin metal films and multilayers." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252236.

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9

Dastoor, Paul Christopher. "The epitaxial growth of thin metal films studied by helium atom scattering." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337943.

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10

Garman, Christopher James. "Electrical characterization of thin film nanostructure templates." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2188.

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Thesis (M.S.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains vi, 70 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 57-61).

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11

Bozeat, Robert John. "Thin film optical waveguides on silicon." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320551.

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12

Tucker, Nigel Paul. "Magnetic structure of Gd thin-film surfaces." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364156.

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13

Gu, Erdan. "Studies in thin film systems and X-ray multilayer film design." Thesis, University of Aberdeen, 1992. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU547604.

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The design and optimization of soft X-ray multilayer film mirrors have been studied using optical theory. Our investigations show that the reflectivity of multilayer films is sensitive to their modulation wavelength and that their reflectivity can be improved by structural optimization. A new design method has been developed which can be used to increase the bandwidth and to change the shape of the reflectivity curves of multilayer film mirrors. Detailed studies of the formation and structure of practical vacuum deposited erbium(Er) thin film systems are presented. It was found that the phase and structure of these deposited films are strongly influenced by deposition conditions and film thickness. On the basis of these studies, very high purity low thicknesss erbium films (&'60 300 AA) with h.c.p. structure have be grown for the first time. The preferred orientation of crystallites and its dependence on deposition conditions in these erbium films are also investigated in detail. We have prepared Er/C multilayer films using the ultra high vacuum electron beam evaporation technique. The compositional periodic structure and intra-layer structure of these multilayer films have been studied using X-ray diffraction. The diffusion and short-range order formation occurring at the interfaces and within layers of C-Er thin-film systems and Er/C multilayer films were investigated by extended X-ray absorption fine structure technique (EXAFS).

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14

Sugden, Stephen. "Thin film adhesion modification by MeV ions." Thesis, University of Surrey, 1991. http://epubs.surrey.ac.uk/843281/.

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The adhesion of a thin films, and in paiticular the way in which such adhesion may be improved by irradiation, is a rather poorly understood field of thin film technology. The radiation enhanced adhesion effect has been investigated through the use of Ultra High Vacuum sample preparation, analysis and irradiation techniques, in order to gain control over surface and interface composition. In the systems studied, films deposited on atomically clean surfaces show good adhesion, and no evidence of enhancement due to irradiation is observed in the case of such clean interfaces. The results are entirely consistent with the radiation enhanced adhesion phenomenon being due to radiolytic effects on contaminant containing layers at the film/substrate interface. In addition, on silicon substrates the observations highlight the superiority of thermal cleaning over low energy sputtering as a route for producing a clean surface. A model of the radiation enhanced adhesion observations for dirty interface systems is developed, which takes into account the two dimensional nature of the ion energy deposition process. All the observations on such systems are broadly consistent with an activation energy for the process of approximately 5eV. This value is sufficiently large to bring about chemical bonding rearrangement at the critical film/substrate interface.

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15

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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16

Rocha, Luciana Sarabando da. "Thin mercury film electrodes in dynamic speciation studies of metals." Doctoral thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/3083.

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Doutoramento em Química
No presente trabalho, foi avaliado o desempenho e a aplicabilidade do eléctrodo de filme fino de mercúrio, em estudos de especiação dinâmica de metais vestigiais. Para tal, foram utilizadas duas técnicas electroanalíticas de redissolução: a clássica Voltametria de Redissolução Anódica (ASV) e a recentemente desenvolvida, Cronopotenciometria de Redissolução com varrimento do potencial de deposição (SSCP). As propriedades de troca-iónica e de transporte de massa de películas mistas preparadas a partir de dois polímeros com características distintas, o Nafion (NA) e o 4-Poliestireno sulfonato de sódio (PSS), foram avaliadas, antes da sua aplicação no âmbito da especiação de metais. Estas películas de NA-PSS demonstraram uma elevada sensibilidade, reprodutibilidade, estabilidade mecânica, bem como, propriedades de anti-bloqueio adequadas na modificação química do eléctrodo de filme fino de mercúrio (TMFE) e, na sua aplicação na determinação de catiões metálicos vestigiais em amostras complexas, por ASV. Para além disso, o desempenho de membranas do polielectrólito PSS em estudos de voltametria de troca-iónica (IEV) foi estudado. O objectivo desta investigação foi reunir as condições ideais na preparação de películas de PSS estáveis e com uma densidade de carga negativa elevada, de modo a aumentar a acumulação electrostática de catiões metálicos no filme polimérico e por conseguinte, conseguir incrementos no sinal voltamétrico. O desempenho e aplicabilidade do TMFE em estudos de especiação de metais vestigiais foram extendidos à SSCP como técnica analítica. Dada a elevada sensibilidade e resolução evidenciada pelo TMFE, este revelou ser uma alternativa adequada aos eléctrodos de mercúrio convencionais, podendo ser utilizado durante um dia de trabalho, sem degradação aparente do sinal analítico de SCP. As curvas de SSCP obtidas experimentalmente utilizando o TMFE estavam em concordância com aquelas previstas pela teoria. Para além disso, a constante de estabilidade (K) calculada a partir do desvio do potencial de meia-onda, para dois sistemas metal-complexo lábeis, aproxima-se não só do valor teórico, como também daquele obtido utilizando o eléctrodo de mercúrio de gota suspensa (HMDE). Adicionalmente, o critério experimental de labilidade inerente a esta técnica foi validado e o grau de labilidade para um dado sistema metal-complexo foi determinado, utilizando o filme fino de mercúrio depositado sob um eléctrodo rotativo (TMF-RDE). Este eléctrodo é muito útil na determinação de parâmetros cinéticos, como é o caso da constante de velocidade de associação (ka), uma vez que as condições hidrodinâmicas, durante a etapa de deposição, se encontram bem definidas.
In the present work the performance and applicability of the thin mercury film electrode (TMFE) in the dynamic speciation of trace metals was investigated. Two different electroanalytical stripping techniques were used: the classical anodic stripping voltammetry (ASV) and a recent developed technique, scanning stripping chronopotentiometry (SSCP). The ion-exchange and the mass transport features of novel mixed coatings of two sulfonated cation-exchange polymers with dissimilar characteristics, Nafion (NA) and poly(sodium 4-styrenesulfonate) (PSS) were evaluated, prior to its application in the field of trace metal analysis. Suitable NA-PSS polymer coatings could be used in the modification of TMFE, presenting a high sensitivity, reproducibility, mechanical stability and adequate antifouling properties in the ASV determination of trace metal cations in complex media. Also the features of the PSS polyelectrolyte layers for ion-exchange voltammetry (IEV) were evaluated. The goal was to search for the best conditions to obtain stable PSS coated electrodes, which could present high negative charge densities in order to enhance the electrostatic accumulation of cations within the film, thus enlarging the ASV signal. The applicability and performance of the TMFE in the trace metal speciation studies, by SSCP, were for the first time exploited. The optimized TMFE presented a high sensitivity and resolution, being an excellent complement to the conventional mercury electrodes and could be use for 1-day term with no significant variation in the SCP analytical signal and no apparent degradation. The calculated SSCP curves were in excellent agreement with experimental data at the TMFE and the stability constant (K), calculated from the shift in the SSCP half-wave potential, of two labile metal-complex systems were in good agreement with the ones obtained using the conventional Hanging mercury drop electrode (HMDE) and those predicted by theory . Additionally, the experimental lability diagnosis inherent to the SSCP technique was validated and a rigorous quantification of the lability degree was made. Due to the well defined hydrodynamic conditions at the thin mercury film rotating disk electrode (TMF-RDE), during the deposition step, this electrode is quite valuable in the determination of kinetic parameters, like the association rate constants (ka).

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17

Beckel, Daniel. "Thin film cathodes for micro solid oxide fuel cells." kostenfrei, 2007. http://e-collection.ethbib.ethz.ch/view/eth:29741.

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18

Flack, Natasha. "Thin film components for solid oxide fuel Cells (SOFCs)." Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2007271/.

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Thin film components for solid oxide fuel cells (SOFCs) have been investigated in this thesis. This work focuses on electrolyte materials such as samarium doped ceria (SDC) and cathode materials including neodymium barium cobalt oxide (NBCO) and barium calcium yttrium iron oxide. Single layer growth of NBCO or SDC is achieved on single crystal strontium titanate (001) before these materials were grown via pulsed laser deposition as a bi-layer and multilayers. Ordered NBCO required deposition at 850°C, whereas it was found that the SDC grew with a lower surface roughness at lower temperatures of around 650°C. The motivation was to investigate how the conductivity is affected by the interfaces between these layers, as motivated by previous studies of yttrium stabilised zirconia (YSZ) with strontium titanate (STO). NBCO was found to be unstable at the temperatures required for AC impedance measurements. From the transmission electron microscopy (TEM) and Energy Dispersive X-ray (EDX) data there is likely migration of Nd into the SDC layers. The interfaces are also less sharp for the multilayer films deposited at the higher temperature for the SDC growth. However, in all cases the SDC growth appears more favourable in the TEM when compared to the NBCO, with some regions even showing Co-metal and fluorite structures potentially attributed to Co-Ox where we would expect to see the perovskite block. Thin films of barium calcium yttrium iron oxide were grown on single crystal strontium titanate (001). The material is a candidate cathode for solid oxide fuel cells (SOFCs) and in the intermediate temperature (IT) region at 600°C the in-plane AC conductivity of the thin film is found to be 30.0Scm-1, significantly enhanced over 3.5Scm-1 found for the polycrystalline form. This is assigned to reduction of the grain boundary density and alignment of the planes predicted to have the highest electronic and ionic conductivities. The symmetry of the film appears to be tetragonal within the resolution of the measurements employed, as opposed to the orthorhombic symmetry of the bulk phase, which may be attributed to the in-plane structural match between the cubic STO substrate and the grown layer. Three potential geometries investigating both single and double-sided growth for measuring the area specific resistance of thin films are discussed and an experimental prototype constructed and tested.

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19

McQuillan, Scott. "Electromagnetic waves in Langmuir Blodgett thin film microstructures." Thesis, Queen Mary, University of London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271335.

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20

Sethu, Murugesan. "Performance studies of thin film electroluminescent (TFEL) devices." Thesis, Nottingham Trent University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250453.

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21

Lee, Myoung-Bok. "The growth and spectroscopic characterisation of ultra-thin aluminium oxide films on single crystal metal surfaces." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309877.

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22

Barnes, C. J. "Adsorption of metals on single crystal substrates." Thesis, University of Liverpool, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234834.

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23

Loh, Kian Ping. "Growth studies and surface modification of thin film diamonds." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320658.

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24

Farrar, Simon Richard. "Excimer laser ablation characterisation for superconducting thin film applications." Thesis, University of Hull, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282366.

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25

Xu, Jiansheng. "Characterisation and magneto-optical enhancement of thin film TbFeCo." Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317538.

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26

Rose, John. "Nanomagnetic and nanostructural studies of thin film magnetic systems." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241740.

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27

Zahrir, A. "Thin film growth and characterization on high temperature superconductors." Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335477.

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28

Huq, Syed Ejazul. "Thin film deposition by the ionized cluster beam method." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304288.

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29

Coxon, Penelope Anne. "Polycrystalline silicon thin-film transistors for large-scale microelectronics." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358595.

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30

Yalamanchili, Hyma. "Dynamic bandgap tuning of solid thin film photonic crystal structures." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/10976.

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Thesis (M.S.)--West Virginia University, 2010.
Title from document title page. Document formatted into pages; contains viii, 95 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 89-95).

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31

Simrick, Neil Jonathan. "Patterned thin film cathodes for micro-solid oxide fuel cells." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/11910.

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32

Akizuki, Makoto. "Gas Cluster Ion-Solid Surface Interaction and Thin Film Formation." Kyoto University, 1999. http://hdl.handle.net/2433/181783.

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33

McNeill, Debra. "Investigation of single shot laser ablation of thin metal films using non-resonant and surface plasmon absorption." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361276.

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34

Loto, Oluwasayo. "Transistors en diamant pour électronique de puissance : études des matériaux et procédés technologiques." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT129.

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Avec la prise de conscience du changement climatique et le dévelopement des sources d’énergies renouvelables, une demande accrue pour une électronique de puissance plus fiable et plus efficace apparait. L’électronique de puissance basé sur les semi-conducteurs à grand gap (carbure de silicium, nitrure de gallium et diamant) vont apporter une réelle amélioration par rapport aux systèmes actuels basés sur des composants au silicium. Ces améliorations concernent en particulier une réduction des pertes, une plus grande tension de bloquage, une amélioration de l’efficacité et de la fiabilité des composants, mais aussi en réduisant les exigences thermiques.Le diamant, bien connu pour sa valeur en joaillerie, possède des propriétés électriques et thermiques très utiles pour l’électronique de puissance. Différent type de design et architectures de dispositifs ont été fabriqués à l'aide de diamant semi-conducteur avec ses caractéristiques électriques prometteuses et pouvant ainsi être intégré à des systèmes. Un dispositif Metal-Oxyde-Semiconductor-Field-Effect-Transistor (MOSFET) en diamant pseudo-vertical offre une densité de courant élevée ainsi que des valeurs de résistance et de claquage élevées nécessaires dans les systèmes haute tension.L’objectif de cette thése est de fabriquer le premier MOSFET de puissance diamant à effet de champ pseudo-vertical avec des valeurs de claquage allant jusqu’à 6,5 kV (20 mOhm.cm-2, 200 ° C). Ce travail porte sur la maîtrise des différents processus impliqués dans la réalisation du dispositif en commençant par la caractérisation du substrat cristallin de diamant suivi des croissances épitaxiales, la microfabrication et pour finir la caractérisation de dispositifs.Dans cette thèse, les étapes nécessaires à la réalisation du MOSFET de puissance pseudo-vertical sont présentées ainsi que trois étapes critiques dans la réalisation du dispositif, qui sont les problèmes liés au substrat, la propagation de défauts à travers les différents empilements de couches et la fiabilité de l'oxyde de grille sont abordés. Le choix de substrats de qualité sans défauts de polissage et avec une faibles densités de dislocations est nécessaire pour une croissance de qualité des différentes couches épitaxiées. Différents substrats ont été achetés et caractérisés. Le type de substrat le plus approprié pour la croissance d'épitaxie de qualité est déterminé après caractérisation par topographie à rayons X, mesures de cathodoluminescence et mesures électriques. La propagation des défauts est inévitable durant la croissance des quatre couches d’épitaxie successives nécessaires à la fabrication du transistor MOSFET pseudovertical. L’apparition de défauts peut provenir des différentes concentrations d’impuretés et du type de dopage entrainant une modification du réseau cristallin et la création de contrainte à l'interface. La topographie aux rayons X et les rocking curves ont été utilisées pour étudier les couches après croissance. Une solution pour effectuer une amélioration dans la croissance de cet empilement de couche est proposé.La fiabilité de la grille est généralement source de préoccupation dans les composant de type MOS. Le décalage de la tension de seuil pendant le fonctionnement est une conséquence des charges présentes dans l'oxyde et des états d'interface du dispositif. Un dispositif capacité MOS de type p a été utilisé pour étudier ce phénomène de manière expérimentale. L'influence du recuit post-oxydation à haute température s'est avérée bénéfique pour obtenir des paramètres d'oxyde de grille stables. Le décalage de la tension de bande plate a également été exploré par des mesures de stress en tension.Toutes les étapes nécessaires à la fabrication du transistor ont ainsi été mises au point séparément, et la technologie a été validée par la réalisation et la caractérisation électrique de transistors Metal-Semiconducteur FET et diodes Schottky
Due to the increase in climate change awareness and development of renewable energy sources, there is an increasing demand for more reliable and efficient power electronics at the point generation, transmision and consumption. Power electronic devices based on wide bandgap semiconductor materials (SiC, GaN and Diamond) will result in substantial improvements in the performance of power electronics systems compared to silicon based devices. They will offer higher blocking voltages, improved efficiency and reliability, as well as reduced thermal requirements.Diamond, though mostly known for its gem value has electrical and thermal properties that are highly beneficial for power electronics. Various device types and device architecture such as diodes, MESFETs and MOSFETS have been made using semiconducting diamond with promising electrical characteristics that could see it incorporated into systems. A pseudo vertical diamond MOSFET device offers possible high current density as well low resistance and high breakdown values needed in high voltage power systems.The aim of this work is to fabricate the first pseudovertical diamond power MOSFET with breakdown values of up to 6.5 kV (20 mOhm.cm-2, 200°C. This work focuses on mastering the series of process involved in the device realization from substrate characterization through epilayer growth to the device microfabrication and the characterization.In this thesis, the detailed steps involved in realizing the pseudovertical power MOSFET has be presented and three critical challenges in the device realization namely substrate related issues, defect propagation through stacked epilayers and the gate oxide reliabiliy has been addressed. The choice of quality substrates free of polishing defects and with low dislocation densities is needed for quality epilayer growth. Different substrates has been procured and characterized. The best substrate type for quality epilayer growth determined after characterization by x-ray topography, cathodoluminescence and electrical measurements have been proposed. Defects propagation was observed in the four stacked epilayer growth needed for the pseudovertical MOSFET transistor. The occurence of defects seems to arise from different impurity concentrations and doping type leading to lattice mismatch and strain in the layers. X-ray topography and rocking curve imaging has been employed to study the grown layers. A method for improved stacked layer growth has also been proposed. The reliability of the gate stack is usually a concern for MOS based devices. The shift in the threshold voltage during operation is a consequence of oxide and interface charges in the device. A p-type MOSCAP device was used to study this phenomenon experimentally. The influence of high temperature post oxidation annealing was found to be beneficial for stable gate oxide parameters. The shift in the flatband voltage has also been monitored through bias stress measurements. The maximum effective charge 9.8E-11 cm-2 as a result of flatband shift was obtained. This value is the same order of magnitude as those observed in state of the art and commercially available SiC devices. All the steps necessary for the transistor fabrication has been developped independently , and technology has been validated by the fabrication and electrical characterization of MESFET and Schottky diodes

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35

Heutz, Sandrine Elizabeth Monique. "Structural, spectroscopic and morphological properties of molecular thin film heterostructures." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252184.

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Swift, Michael Joseph Robert. "Aspects of single crystal and thin film high field electroluminescence." Thesis, University of Hull, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304437.

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Kilvert, Paul Vyvyan Andrew. "The synthesis and evaluation of Langmuir-Blodgett thin film materials." Thesis, University of Hull, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292691.

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38

Connolly, M. P. "Surface plasmon polaritons in thin film structures : calculations & experiment." Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333810.

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39

Al-Samarrie, A. K. "The application of thin film and microwave technology in instrumentation." Thesis, University of Salford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334054.

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40

Gottschalg, Ralph. "Environmental influences on the performance of thin-film solar cells." Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/35675.

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The response of thin-film photovoltaic devices to changes in the environment is not well understood. There are a large number of conflicting reports, reflecting largely the superimposed nature of the environmental effects. A separation of the effects is not often attempted mainly because of the lack of appropriate spectral data. An experimental system has been designed and operated to facilitate the separation of the environmental effects, including spectral effects. This involves measurements in a controlled laboratory environment as well as outdoor monitoring. Furthermore, a number of analysis tools have been developed and tested for their suitability. In order to develop a system model, the applicability of parametric models for thin-film devices is probed. The thermal variation of the underlying physical parameters is investigated and problems of describing thin-film devices with parametric models are discussed.

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41

Schauer, Janine-Christina. "PECVD-deposition and characterisation of C-Si thin film systems on metals." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985145587.

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42

Clough, Francis John. "The performance and stability of hydrogenated amorphous silicon thin film transistors." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386233.

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43

Giles, Luis Felipe. "Characterization and control of crystallographic defects in thin film SIMOX materials." Thesis, University of Surrey, 1994. http://epubs.surrey.ac.uk/844322/.

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Crystallographic defects present in the silicon over layer of thin (< 1000 A) SIMOX material have been characterized using a newly developed etchant and by transmission electron microscopy. Rutherford backscattering spectroscopy has also been used to determine the chemical composition and thickness of the synthesised layers. The thin SIMOX layers were produced by two different methods, namely (i) sacrificial oxidation of the silicon over layer of thick (2000 A) SIMOX films and (ii) low energy O+ implantation. The main crystallographic defects present in materials prepared by sacrificial oxidation are threading dislocations and oxidation induced stacking faults (OISF) whose density and size depends mainly upon the oxidation conditions (temperature, time) and also on the number of nucleation sites present before oxidation. The nucleation of these OISF has been investigated and it has been observed that stacking fault (SF) complexes are the main nucleation sites. The density of threading dislocations within the Si over layer does not increase during oxidation. The lowest density of OISF (5.0x102 cm-2) was observed in layers thinned by dry oxidation although some layers contained up to 5.0x105 cm-2. This difference in OISF densities was attributed to differences in the densities of the SF complexes before oxidation. Thin film SIMOX structures formed by low energy implantations also contain two principal defect types namely, threading dislocations and stacking fault complexes, where the densities depend upon the implantation and annealing conditions, A low density of threading dislocations is only obtained when parameters, such as dose and implantation temperature are optimised. Furthermore, it is also observed that thermal and mechanical stresses produced in the silicon over layer during implantation or annealing, need to be minimised in order to obtain low defect density material. It has been shown by whole wafer defect mapping of six inch SIMOX wafers implanted under optimised conditions, that a uniform distribution of defects can be achieved, having an average defect density as low as 1.0x104 cm-2. Additionally, the effects of implantation damage on the formation of secondary defects have also been investigated. The results have shown that the coalescence of point defects generated during implantation produce a high density of dislocation loops that, depending upon the annealing treatment, develop into threading dislocations or OISF. These experiments confirm that careful optimisation of the processing conditions, such as implantation temperature and dose uniformity, can significantly reduce defect densities thus enhancing the prospect of thin film SIMOX as a suitable substrate for fully depleted MOS devices.

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Hadland, Erik. "Thin Film van der Waals Heterostructures containing MoSe2 from Modulated Elemental Precursors." Thesis, University of Oregon, 2019. http://hdl.handle.net/1794/24520.

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Transition metal dichalcogenides (TMDs) are naturally occurring layered materials that have attracted immense research interest due to their high degree of chemical tunability. In particular, MoSe2 has been the focus of significant investigation stemming from reports that it converts to a direct band gap semiconductor material at ultralow dimensions. Yet, as more and more is learned about increasingly thin MoSe2, efforts are now aimed at imparting the novel functionality of MoSe2 into van der Waals heterostructures. This dissertation focuses on synthesis and characterization of novel MoSe2-based nanolaminate structures that have been self assembled from modulated elemental precursors. The first section describes a new treatment of x-ray fluorescence spectroscopy data and its use as a powerful probe for determining the absolute composition per unit area of a thin film with sub-monolayer accuracy. While this has widespread application in the thin film world, it is particularly useful for MER synthesis in the calibration of modulated elemental precursors. In order to crystallize a target structure, it is imperative to deposit the correct number of atoms, which is now possible with greater precision. The second section shows the importance of rotational (i.e. “turbostratic”) disorder on lowering cross-plane thermal conductivity in two systems—MoSe2 and the (SnSe2)1(MoSe2)1.32 heterostructure. The binary systems exhibits ultralow thermal conductivity that rivals that of WSe2, yet some interlayer atomic registry was noted in TEM images. By interleaving layers of MoSe2 with SnSe2—which also possesses hexagonal symmetry, but has a significantly larger basal plane—the cross-plane thermal iv conductivity was depressed to the lowest reported value in the literature for a fully dense solid. The final section presents the synthesis and characterization of a new, ternary phase of Bi|Mo|Se. The structure consists of alternating layers of a “puckered” rock salt BiSe lattice and nanosheets of MoSe2. Notably, the MoSe2 sublattice consists of a mixture of the semiconducting 2H phase (~60%) and the metallic 1T phase (~40%). This is the result of electron injection from the BiSe into the conduction band of the MoSe2, which is known to undergo a rearrangement upon reduction. This dissertation includes previously published and unpublished coauthored materials.
2021-04-30

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Ginige, Ravin. "Switching phenomena in stearic acid MIM structures and conduction phenomena in stearic acid thin films on metal and semiconductor substrates." Thesis, Brunel University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277418.

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Yoon, Jongsik. "Nanostructured thin films for solid oxide fuel cells." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3164.

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Pohl, John E. T. "The electrical properties of bulk polycrystalline and thin film high temperature superconductors." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315041.

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Ma, Jun. "The deposition and electro-optical properties of thin film zinc sulphide phosphors." Thesis, University of Ulster, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388877.

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Bayhan, Murat. "Preparation and characterisation of n-CdS/p-CdTe thin film solar cells." Thesis, Durham University, 1994. http://etheses.dur.ac.uk/1697/.

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Kunz, Oliver Photovoltaics &amp Renewable Energy Engineering Faculty of Engineering UNSW. "Evaporated solid-phase crystallised poly-silicon thin film solar cells on glass." Publisher:University of New South Wales. Photovoltaics & Renewable Energy Engineering, 2009. http://handle.unsw.edu.au/1959.4/43644.

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The cost of photovoltaic electricity needs to be significantly reduced in order to achieve a high electricity market penetration. Thin-film solar cells have good potential to achieve such cost savings though (i) large-area deposition onto low-cost foreign substrates, (ii) more streamlined processing, (iii) monolithic cell interconnection, and very efficient use of the expensive semiconductor material. Polycrystalline silicon (poly-Si) on glass is a promising technology for the cost-effective large volume production of PV modules since it (i) makes use of an abundant raw material, (ii) is non-toxic, (iii) does not suffer from light-induced degradation, and (iv) does not rely on TCO layers. Usually plasma enhanced chemical vapour deposition (PECVD) is used for the layer formation. This thesis explores the use of e-beam evaporation as deposition method since it is potentially much faster and cheaper than PECVD. The resulting solar cells are referred to as EVA (from EVAporation). Two inherent shunting mechanisms in EVA cells are demonstrated to be shunting through sub-micron sized pinholes when the back electrode is deposited and shunting between the emitter and the absorber layer at the glass-side electrode. Through the improved understanding of these shunting mechanisms it was possible to develop a suitable metallisation scheme for EVA cells using an aligned deposition of emitter and back surface field line contacts and a specially developed shunt mitigation etching technique. For the first time appreciable efficiencies of up to 5.2% were demonstrated on this material. It was also shown that only very lightly doped absorber layers can lead to the required high short-circuit currents in EVA cells. The resulting cells are currently completely limited by space charge region recombination occurring with comparatively low ideality factors of only ~ 1.4 This thesis also demonstrates the usefulness of Jsc-Suns measurements and investigates optical loss mechanisms in the current devices. Advanced modelling of distributed series resistance effects, influencing Suns-Voc, m-Voc and Jsc-Suns curves, is employed. PC1D modelling is used to extract relevant device parameters. In this work it was found that the diffusion length in the best EVA cells is longer than the absorber layer and that insufficient light trapping is currently the major hurdle to higher cell efficiencies. From the obtained results it can be concluded that EVA solar cells are promising candidates for the low-cost and high-volume production of solar modules.

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Dissertations / Theses on the topic 'Solid thin film metals'

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