Made available in DSpace on 2014-06-11T19:25:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-19Bitstream added on 2014-06-13T20:53:34Z : No. of bitstreams: 1 moralesmorales_o_me_ilha.pdf: 672260 bytes, checksum: 722e9d33ee2b26bf51fb6c4b9a1ef435 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho, o objeto de estudo foi células Solares CdS/CdTe. Estas células usam o filme de sulfeto de cádmio (CdS) como semicondutor do tipo n e o filme de telureto de cádmio (CdTe) como semicondutor do tipo p. O recorde mundial, alcançado no laboratório, para estas células é 16,5% de eficiência. Nos Laboratórios do Departamento de Física e Química de Unesp - Ilha Solteira, este trabalho é pioneiro na fabricação de Células Solares de CdS/CdTe. Para realizar este trabalho foi necessário melhorar o sistema de deposição por spray de SnO2:F já existente, acondicionar o sistema de banho químico para deposição do filme de CdS e implementar o sistema de sublimação para depositar a camada de CdTe. Todos estes sistemas de deposição de filmes finos foram implementados no laboratório do Grupo de Desenvolvimento e Aplicação de Materiais (GDAM). A fabricação da Célula Solar CdS/CdTe consistiu na deposição sequencial sobre vidro de a) Eletrodo condutor transparente utilizando óxido de estanho dopado com Flúor (SnO2:F) pelo método de spray, com controle automático de jato; b) deposição de sulfeto de Cádmio (CdS) pelo método de banho Químico (CBD); c) deposição de Telureto de Cádmio (CdTe) pela técnica de sublimação no espaço fechado (CSS) e d) deposição do contato metálico traseiro de prata por colocação de camada liquida e posteriormente a melhora deste contato com grafite-prata. A estrutura final destas células foi: Vidro/SnO2:F/CdS/CdTe/contato. A caracterização estrutural e óptica das camadas destas células foi realizada pelas técnicas de DRX e UV-vis; os parâmetros elétricos das células foram determinados pela construção da curva I-V. A camada CdTe da célula solar foi tratada termicamente com dicloreto de cádmio (CdCl2) para comparar a sua eficiência com outra célula que não foi tratada... / The object of this work was the study solar Cells CdS/CdTe. These cells use a cadmium sulfide film as an n-type semiconductor and a cadmium telluride film as a p- type semiconductor The world record for maximum efficiency achieved in laboratory for these cells is 16.5%. In laboratories of Departament of Physics and Chemistry of Unesp-Ilha Solteira, this work is a pioneer in the manufacture of CdS/CdTe Solar Cell. To carry out this work it was necessary to improve the existing system of Spray deposition of SnO2: F, conditioning of the system for chemical bath deposition of CdS film and manufacture the sublimation system to deposit the CdTe layer. All of these systems for the deposition of thin films were developed in the laboratory. The manufacture of CdS/CdTe solar cell consisted of sequential deposition on glass of a) transparent conductive tin oxide doped with fluorine (SnO 2:F) using automatic control system of the spray; b) deposition of cadmium sulfide (CdS) for method (CBD); c) deposition of cadmium telluride for technique in closed space sublimation (CSS) and d) the rear metallic contact of silver was deposited by placing the liquid layer and subsequent improvement of contact with graphite-silver. The final structure of cell used in this work was: glass/SnO2:F/CdS/CdTe/contact. The CdTe solar cell layer was heat treated with cadmium dichloride (CdCl2) to compare its efficiency with another cell that was not treated with cadmium dichloride. Then we investigated the performance of only putting back metal contact layer of silver of silver and silver-graphite layer, the latter was giving better results, achieving an efficiency is a well more than 5%

Twenty different materials have been successfully deposited as Langmuir- Blodgett monolayer films. All exhibit second harmonic generation (SHG) when irradiated with laser light at 1064 nm. E-1-docosyl-4-{2-(4-dimethylami nophenyl)ethenyl}quinolinium bromide (C22H45QHBr) and E-1-docosyl-4-{2-(4-dimethy laminonaphthyl)ethenyl}quinolinium bromide (C22H45QNBr) have been deposited separately as multilayer films. They form Y-type structures when deposition is alternated with the material N-docosyl-4- methylquinolinium bromide. The nonlinear responses are quadratic up to 20 and 10 bilayers respectively and the response from the thick films is only 2 orders less than that produced by a Y-cut quartz plate. Similar results were obtained with C22H45QHBr when interleaved with 4,4'-dioctadecyl-3,5,3', 5'- tetra me thyldipyrrylmethenehydrobromide. Ellipsometry studies of the 10 bilayer film of C H45QNBr indicate that the structure is interdigitated. This explains the stability of the film which gave the same SH response up to 6 months after deposition. A 10 bilayer films has also been fabricated using E-1- docosyl-4-{2-(4-{2-(4-dimethylaminophenyl)ethenyl}benzyl)ethenyl}pyridinium bromide (C22H45PBHBr) alternated with E-1-docosy1-4-{2-(4-methylphenyl)ethenyl}pyridinium bromide (C22H45PT). E-1-octadecyl-4-{2-(4-methyloxyphenyl)ethenyl}pyridinium iodide and E-1- methyl-4-{2-(4-octadecyloxyphenyl)ethenyl}pyridinium iodide have been fabricated into monolayer films that are transparent at 1064 and 532 nm, therefore resonant enhancement does not contribute to their nonlinear response which is attributed solely to charge transfer in the molecule. Mixed solutions of E-1-octadecyl-4-{2-(4-methyloxyphenyl)ethenyl}pyridinium iodide and sodium octadecylsulphate (C1SH37OSO3 Na+) have been deposited as very stable monolayers. The nonlinear response from the mixed film offers a significant improvement upon the performance of the film containing pure hemicyanine. Novel zwitterionic materials have been fabricated as LB monolayers that also exhibit SHG.

Conferencia que trata sobre las industrias culturales y del entretenimiento enfocadao en la empresa Tondero a cargo de Miguel Valladares su fundador y director de TONDERO. Realizada el 15 de mayo de 2018 en el auditorio principal del campus San Miguel de la UPC.

Made available in DSpace on 2014-06-11T19:30:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-10Bitstream added on 2014-06-13T19:00:06Z : No. of bitstreams: 1 goncalves_tm_me_bauru.pdf: 1834288 bytes, checksum: 9d41cc9f6ebce4061033368ea92fec9c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Filmes finos de carbono amorfo hidrogenado contendo silício e dopados com flúor foram produzudos pelos métodos de Deposição de Vapor Químico Assistido e Plasma (PECVD) e Deposição e Implantação Iônica por Imersão em Plasma (PIIID). Para PECVD foi utilizada uma pressão total de gases/vapor de 100 mTorr e inicialmente, 100W de potência de excitação. A proporção dos gases foi estudada, mantendo a concentração do hexametildisiloxano (HMDSO) em 75% e variando a proporção do argônio (Ar) e do hexafluoreto de enxofre (SF6). As porcentagens de flúor utilizadas na alimentação do plasma variaram em 0,6,9 e 12,5%. Visando maior concentração atômica de flúor na estrutura dos filmes, determinou-se a proporção de gases/vapor mais apropriada (75% HMDSO, 19% Ar e 6% SF6), e posteriormente, foi realizado um novo estudo da potência de excitação. Variando a potência entre 40 e 70 W, 50 W foi considerada como sendo a melhor condição de excitação para a descarga luminosa, considerando os efeitos causados pela corrosão relacionada ao flúor e a incorporação do elemento. Um estudo sobre as mesmas proporções foi realizada pela técnica de PIIID, com uma pressão total de 50 mTorr, potência de 50 W e pulsos negativos com magnitude de 800 V. Para este método o filme produzido com 12,5% de SF6 foi escolhido como sendo a melhor opção, tendo em vista que apresentou a maior quantidade atômica de flúor em sua estrutura. Posteriormente, a intensidade dos pulsos aplicados foi variada entre 544 e 14801 V, onde verificou-se que o aumento da intensidade dos pulsos resulta na diminuição da incorporação de flúor / Hydrogenated amorphous carbon films containing silicon and doped with fluorine were produced by two methods: Plasma Enhanced Chemical Vapor Deposition (PECVD) and Deposition (PIIID). For PECVD a total pressure of 100 mTorr was used at a excitation power of 100 W. The gas/vapor proportion was studied, keeping 75% hexamethyldisiloxane and varying the argon (Ar) and sulfur hexafluoride (SF6) ratio. The following proportions of SF6) ratio. The following proportions of SF6 were examined: 0, 6, 9 and 12.5%. Aiming for the highest atomic concentration of fluorine in film structure the best condition (75% HMDSO, 19% Ar and 6% SF6) was determined and a new study of the influence of the radiofrequency power. Considering the corrosion effects gernerated by fluorine in the plasma, variation of the applied power between 40 and 70 W, allowed the selection of 50 W as the best conditions. A study employing the same proportior PIIID was performed using 50 mTorr of total pressure, an applied power of 50 W and a pulse bias of 800 V. Considering the results of the chemical characterizations, films were produced with 12.5% of SF6 in the plasma feed. Subsequently, bias voltage was varied between 544 and 1480 V, where it was observed that the increasing the pulse bias decreased the fluorine concentration in film structure

Made available in DSpace on 2014-06-11T19:30:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-29Bitstream added on 2014-06-13T19:39:42Z : No. of bitstreams: 1 silva_vdl_me_bauru.pdf: 1285191 bytes, checksum: cca22db63612f5a769cb9b3084296342 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo principal deste trabalho é elucidar quais são os mecanismos de transporte de portadores de carga presentes na interface entre SnO2 e o contato metálico, pois tal conhecimento é fundamental para a aplicação na eletrônica. Além disso, é objetivo aqui também, estudar características de transporte em SnO2 dopado com alguns íons terras-raras. As amostras de SnO2 dopadas em Eu3+ e Ce3+ utilizadas nesta pesquisa foram sintetizadas a partir do método sol-gel e os filmes finos depositados pela técnica dip-coating. Os contatos estudados foram feitos a partir dos metais In, Sn e Al, depositados via evaporação resistiva. Medidas de resistência em função da temperatura nas amostras dopadas com Eu indicaram uma variação significativa da resistividade, de até 10 vezes, quando alterado o metal do contato. Isto se deve a diferença entre a função de trabalho de cada metal, que consequentemente acarreta em variação da barreira de potencial na junção metal-semicondutor. Pela característica das curvas de corrente medida em função da tensão aplicada, observou-se que os dois mecanismos de condução elétrica dominantes na interface são a emisssão termiônica, quando em baixas temperaturas e tensões de menor intensidade, e o tunelamento através da barreira, quando em temperaturas mais altas e tensões de maior intensidade. Com base nesses resultados e na aplicação do método proposto por Rhoderick estimou-se os valores da altura da barreira de potencial na junção metal-semicondutor, em 132 meV, 162 meV e 187 meV para os metais In, Al, Sn, respectivamente. Além disso, o tratamento térmico realizado nas amostras promoveu, de modo geral, a diminuição da resistividade do dispositivo devido, provavelmente, ao estreitamento da barreira de potencial e consequente aumento da... / The main goal of this work is the verification of electrical transport mechanisms of charge carriers at the interface between SnO2 and the metallic contact, because this knowledge is fundamental for electronic applications. Besides, another goal here is to investigate transport characteristics of rare-earth doped SnO2 samples doped with Eu3+ and Ce3+ used in this research were made from the sol-gel method and the thin films were deposited via dip-coating technique. The analyzed contacts were deposited from metals In, Sn and Al, via resistive evaporation technique. Resistance as function of temperature measurements applied to Eu-doped samples indicates a significant resistivity, up to 10 times, when the contact metal is varied. This is due to the differences in the work function of each metal, leading to variation in the potential barrier at interface of the metal-semiconductor junction. The characteristics of the current-voltage curves yield two dominant electrical mechanisms at the interface: thermo-ionic emission, for low temperatures and higher applied bias, and quantum tunneling through the barrier, when the temperature is higher and so is the applied bias magnitude. Based on these results and the application of the method proposed by Rhoderick, the potential barrier height of metal-semiconductor junction values were evaluated, yielding 132 meV, 162 meV and 187 meV for the metals In, Al and Sn, respectively. Besides, generally speaking, thermal annealing promotes the resistivity decrease, probably due to the potential barrier narrowing, increasing the tunneling probability. The variation of Ce3+ concentration, from 0,1% also leads to variation in the device resistivity, but this is not related to the potential at the junction interface, instead it is related with other bulk factors, as the charge... (Complete abstract click electronic access below)

Magister Scientiae - MSc / The growth of amorphous hydrogenated silicon (a-Si:H) thin films deposided by hot wire chemical vapor deposition (HWCVD) has been studied. The films have been characterised for optical and structural properties by means of UV/VIS,FITR,ERDA, XRD.XTEM and Raman spectroscopy. Low subtrate heater temperatures in the range form 130 to 200 degrees celcius were used in this thesis because it is believed to allow for the deposition of device quality a-Si:H which can be used for electronic photovoltaic devices. Furthermore, low temperatures allows the deposition of a-Si:H on any subtrate and thus offers the possibility of making large area devices on flexible organic substances. We showed that the optical and structural properties of grown a-Si:H films depended critically upon whether the films were produced with silane gas or silane diluted with hydrogen gas. We also showed that it is possible to to deposit crystalline materials at low temperature under high hydrogen dilution ratio of silane gas. / South Africa

No description available.

This article seeks to investigate this balance and to interrogate the difference between horror and terror in an attempt to contribute to the development of a systematic genre typology. A brief history of the genre will be given, after which the focus will fall on contemporary Horror film, paying specific attention to the relationship between violence and horror, the theme of sacrificial violence, and the transgression of ‘natural’ laws. An eclectic approach is followed, drawing from literary theory, theology, psychology, and, of course, film theory.

Epitaxial oxide thin films are used in many technologically important device applications. This work deals with the deposition and characterization of epitaxial WO3 and SrBi2Ta2O9 (SBT) thin films on single crystal oxide substrates. WO3 thin films were chosen as a subject of study because of recent findings of superconductivity at surfaces and twin boundaries in the bulk form of this oxide. Highly epitaxial thin films would be desirable in order to be able to create a device within a film without patterning it, by locally creating superconducting regions (e.g. twins) within an otherwise defect free film by reducing or doping the film with Na. Films were deposited by reactive magnetron sputtering at various temperatures on single crystal SrTiO3 (100) and R-sapphire substrates. X-ray diffraction studies showed that the optimised films were highly (001) oriented, quality of epitaxy improving with decreasing deposition temperature. AFM studies revealed columnar growth of these films. Films were heat treated with Na vapour in order to reduce or dope them with Na. Low temperature measurements of the reduced films did not show existence of any superconductivity. SBT is a ferroelectric oxide and its thin films are attractive candidates for non-volatile ferroelectric random access memory (FRAM) applications. High structural anisotropy leads to a high degree of anisotropy in its ferroelectric properties which makes it essential to study epitaxial SBT films of different orientations. In this study, SBT films of different orientations were deposited on different single crystal substrates by pulsed laser ablation. Highly epitaxial c-axis oriented and smooth SBT films were deposited on SrTiO3 (100) substrates. AFM studies revealed the growth of these films by 3-D Stranski-Krastanov mode. However, these films did not exhibit any ferroelectric activity. Highly epitaxial (116)-oriented films were deposited on SrTiO3 (110) substrates. These films were also very smooth with root mean square (RMS) roughness of 15-20 Å. Films deposited on TiO2 (110) were partially a-/b-axis oriented and showed the formation of c-axis oriented SBT and many impurities. Completely a-/b-axis oriented SBT films were deposited on LaSrAlO4 (110) substrates. Films deposited at non-optimal growth temperatures showed the formation of many impurities. Attempts were also made towards depositing Sr2RuO4 films on LaSrAlO4 (110) substrates, which can act as a bottom electrode for ferroelectric SBT films.

This thesis explores different physical phenomena observed in, or involving thin surface films. Thin surface layers are ubiquitous. Found in nature and used in almost every aspect of daily life, thin surface films are invaluable. While the applications and roles may be varied, to be used effectively, the physical properties of these films and the factors influencing their stability need to be well understood. Surfaces can have a strong effect on the stability of thin films. In thin films of polymer blends, wetting layers rich in one component often form at the film interface prior to phase separation. Here the formation of these wetting layers are seen to result in destabilisation of the film, even when the blend is far from phase coexistence. A spinodal like instability with a characteristic wavelength is shown to form. A theoretical model is developed, which describes the observed behaviour in terms of coupled height and composition fluctuations in the wetting layer. Spin coating is a common technique for the formation of thin polymer films. Films formed in this way however, are often seen to exhibit anomalous properties, which strongly differ from that of the bulk behaviour of the material. Here the rheological properties and stored stresses in spin cast films are explored, with focus on the role that the casting solvent plays in the properties of the film. The results suggest that the observed deviation comes from a lowered density of chain entanglements. The effective viscosity and residual stresses in the as-spun film are seen to strongly depend on the casting solvent properties and the solvent-polymer interactions. The use of organometallic polymers as precursors for the formation of magnetic ceramics is investigated. Emphasis is placed on doping the polymers with metallic compounds prior to pyrolysis, allowing for the formation of technologically interesting metallic alloys, without the need for new polymers to be synthesised. The formation of iron-palladium alloys is demonstrated using this method. These are highly desirable due to their potential use in hard-disk drive technologies. Thin films can be used to influence the optical signature of a material and are widely used in nature to produce vibrant, pure, iridescent colours. Here the optical properties of the tropical plant Selaginella willdenowii are explored. The bright blue colouration is seen to arise from a multilayer lamella structure on the upper surface of the leaves. Light is important to plants, who use it both as an energy source and an environmental signal. Blue iridescence occurs in a wide range of plant species, suggesting that it has some adaptive benefit. These are considered and discussed.