When the size of display panel increased, the RC delay of TFTs became serious. High dielectric (high-k) materials used as the gate oxide can increase the gate oxide capacitance Co, which can induce a higher drain current, and higher aperture ratio. Therefore, low-k materials are used for inter-metal dielectrics. Thus, it can improve the RC delay. LPD-TiO2 film on a-Si and poly-Si technology and characterization of films were described in detail in this thesis. The highest dielectric constant of 11.76 and 29.54, and lowest leakage current density of 5.45¡Ñ10-7A/cm2 at -0.45 MV/cm and 3.11¡Ñ10-1 A/cm2 at 0.45 MV/cm for the O2-annealed of LPD-TiO2film on a-Si and poly-Si can be obtained.

The objective of this thesis is to apply semiconductor etching process technologies on 6 inch P-type Si substrate and produce a mold of Light Guiding Plate (LGP). After evaporate chromium (Cr) onto the Si substrate as etch mask, the thin films were then patterned and subsequently etch by plasma. Different powers were used to compare the cross-sections of the patterns. The results would be the references of Si molding process. Another objective is to fabricate Si-V grooves which can connect the fibers and accurately position fibers. Anisotropic etching of Si-V grooves were formed using EDP solution, and sputtered Ta2O5 was used as the etch mask. At a etching temperature of 1100C, the under cut is 2.5~3mm . Additionally using SiO2 as etch mask by thermo evaporation at 1050¢J .Use EDP solution at 1100C, the under cut is 2.25mm which had a better result.

In this research, the degradation effect of the low temperature polycrystalline silicon TFTs (LTPS TFTs) under dynamic stress was investigated. The experiment results revealed that the degenerate behaviors of n- and p-type poly-Si were different. In p-channel TFT, it was observed that the degradation of threshold-voltage (Vth) was closely associated with the stress frequency of ac stress. The degradation was more serious at low-frequency stress than that at high-frequency stress. The degradation of electrical characteristics of device is mainly dominated by the self-heating enhanced negative bias temperature instability effect. Moreover, the increased temperature around the environment could make the degradation of characteristics more serious, such as Vth shift (fixed charge), degraded S.S (dangling bonds). We suggest that the generation of deep states originated from bond broken at both of grain-boundary and interface state was explained the degradation mechanism of threshold-voltage. In n-channel TFT, the degradation characteristics may be attributed to both of the temperature effect and the hot carrier effect under the different stress frequency. At low-frequency stress, Vth shift (positively) and mobility are increased after 100 seconds stress because of the temperature effect. However, Vth shift (negatively) and mobility are decreased after 500 seconds stress because of the effect of the state creation near the drain regime. At high-frequency stress, the times of the switch is numerous, and result in the on-state current decreased because of the trap state generated.

Investigations made on new materials and their structures for production of particle detectors based on semi-insulating SiC and GaN comprise the technological and applied importance of this study. Innovations in defect control technology, especially, in recognition of extended defects and percolative carrier transport in heavily irradiated detector structures are considered and applied for scientific implementations. These investigations have been performed within a framework of CERN rd50 project. Irradiation by 24 GeV protons varying fluence up to 1016 cm-2 deteriorates rectifying properties of the 4H-SiC particle detectors. Different isotopes produced in 4H-SiC during irradiation by protons have been revealed by gamma spectroscopy. In the non-irradiated GaN material the temperature-dependent variations of leakage current have been unveiled to be caused by the carrier mobility temperature changes. Activation energy values have been extracted for proton radiation induced deep centres in the GaN detectors by thermally stimulated current spectroscopy as well as the isotopes and long-living radio-nuclides have been identified by gamma spectroscopy. In the Si detectors, irradiated by reactor neutrons, the photo-activation energy values have been determined for the deep levels located below the mid-gap by photo-ionisation spectroscopy while isochronal anneals enhance the density of the acceptor-type vacancy-related defects. / Disertacijoje išanalizuoti gilieji centrai didžiavaržiuose Si, SiC ir GaN dariniuose, sietini su didelės energijos protonų bei neutronų spinduliuote sudarytais defektais, atskleistos radiacinių defektų transformacijos po iškaitinimų, didelių energijų spinduliuotės įtaka krūvio pernašai ir pagavai medžiagose, tinkamose jonizuojančiosios spinduliuotės detektoriams, tiriamiems pagal Europos branduolinių tyrimų centro (CERN) projektus. 4H-SiC dariniuose, apšvitintuose 24 GeV/c protonais, išanalizuota elektrinių charakteristikų kaita. Iš šiluma skatinamųjų srovių spektrų nustatytos šiluminės aktyvacijos energijų vertės. Taip pat 4H-SiC dariniuose, apšvitintuose protonų įtėkiais, siekiančiais 1016 cm-2, įvertintas skirtingų spinduliuote sukurtų izotopų kiekis. Neapšvitintose GaN dariniuose nustatyta, kad medžiagos elektrinio laidumo parametrų kaitą nulemia krūvininkų judrio kitimas. Apšvitintuose neutronais GaN dariniuose šiluma skatinamųjų srovių spektroskopijos būdu buvo nustatyti dominuojančių defektų lygmenys. Aptikta, kad po apšvitos 24 GeV/c protonų įtėkiais, siekiančiais 1016 cm-2, GaN susidarė 7Be, 22Na ir kiti ilgaamžiai radionuklidai, kurių atominis skaičius A<70, bei žymiai pakito spinduliuotės detektorių krūvio pernašos savybės. Didžiavaržio silicio detektoriuose po apšvitos reaktoriaus neutronais susidarė visa eilė radiacinių defektų, kuriems priskirtinų giliųjų centrų parametrai buvo įvertinti fotojonizacijos spektroskopijos ir tamsinės srovės temperatūrinių kitimų... [toliau žr. visą tekstą]

Disertacijoje išanalizuoti gilieji centrai didžiavaržiuose Si, SiC ir GaN dariniuose, sietini su didelės energijos protonų bei neutronų spinduliuote sudarytais defektais, atskleistos radiacinių defektų transformacijos po iškaitinimų, didelių energijų spinduliuotės įtaka krūvio pernašai ir pagavai medžiagose, tinkamose jonizuojančiosios spinduliuotės detektoriams, tiriamiems pagal Europos branduolinių tyrimų centro (CERN) projektus. 4H-SiC dariniuose, apšvitintuose 24 GeV/c protonais, išanalizuota elektrinių charakteristikų kaita. Iš šiluma skatinamųjų srovių spektrų nustatytos šiluminės aktyvacijos energijų vertės. Taip pat 4H-SiC dariniuose, apšvitintuose protonų įtėkiais, siekiančiais 1016 cm-2, įvertintas skirtingų spinduliuote sukurtų izotopų kiekis. Neapšvitintose GaN dariniuose nustatyta, kad medžiagos elektrinio laidumo parametrų kaitą nulemia krūvininkų judrio kitimas. Apšvitintuose neutronais GaN dariniuose šiluma skatinamųjų srovių spektroskopijos būdu buvo nustatyti dominuojančių defektų lygmenys. Aptikta, kad po apšvitos 24 GeV/c protonų įtėkiais, siekiančiais 1016 cm-2, GaN susidarė 7Be, 22Na ir kiti ilgaamžiai radionuklidai, kurių atominis skaičius A<70, bei žymiai pakito spinduliuotės detektorių krūvio pernašos savybės. Didžiavaržio silicio detektoriuose po apšvitos reaktoriaus neutronais susidarė visa eilė radiacinių defektų, kuriems priskirtinų giliųjų centrų parametrai buvo įvertinti fotojonizacijos spektroskopijos ir tamsinės srovės temperatūrinių kitimų... [toliau žr. visą tekstą] / Investigations made on new materials and their structures for production of particle detectors based on semi-insulating SiC and GaN comprise the technological and applied importance of this study. Innovations in defect control technology, especially, in recognition of extended defects and percolative carrier transport in heavily irradiated detector structures are considered and applied for scientific implementations. These investigations have been performed within a framework of CERN rd50 project. Irradiation by 24 GeV protons varying fluence up to 1016 cm-2 deteriorates rectifying properties of the 4H-SiC particle detectors. Different isotopes produced in 4H-SiC during irradiation by protons have been revealed by gamma spectroscopy. In the non-irradiated GaN material the temperature-dependent variations of leakage current have been unveiled to be caused by the carrier mobility temperature changes. Activation energy values have been extracted for proton radiation induced deep centres in the GaN detectors by thermally stimulated current spectroscopy as well as the isotopes and long-living radio-nuclides have been identified by gamma spectroscopy. In the Si detectors, irradiated by reactor neutrons, the photo-activation energy values have been determined for the deep levels located below the mid-gap by photo-ionisation spectroscopy while isochronal anneals enhance the density of the acceptor-type vacancy-related defects.

abstract: A primary motivation of research in photovoltaic technology is to obtain higher efficiency photovoltaic devices at reduced cost of production so that solar electricity can be cost competitive. The majority of photovoltaic technologies are based on p-n junction, with efficiency potential being much lower than the thermodynamic limits of individual technologies and thereby providing substantial scope for further improvements in efficiency. The thesis explores photovoltaic devices using new physical processes that rely on thin layers and are capable of attaining the thermodynamic limit of photovoltaic technology. Silicon heterostructure is one of the candidate technologies in which thin films induce a minority carrier collecting junction in silicon and the devices can achieve efficiency close to the thermodynamic limits of silicon technology. The thesis proposes and experimentally establishes a new theory explaining the operation of silicon heterostructure solar cells. The theory will assist in identifying the optimum properties of thin film materials for silicon heterostructure and help in design and characterization of the devices, along with aiding in developing new devices based on this technology. The efficiency potential of silicon heterostructure is constrained by the thermodynamic limit (31%) of single junction solar cell and is considerably lower than the limit of photovoltaic conversion (~ 80 %). A further improvement in photovoltaic conversion efficiency is possible by implementing a multiple quasi-fermi level system (MQFL). A MQFL allows the absorption of sub band gap photons with current being extracted at a higher band-gap, thereby allowing to overcome the efficiency limit of single junction devices. A MQFL can be realized either by thin epitaxial layers of alternating higher and lower band gap material with nearly lattice matched (quantum well) or highly lattice mismatched (quantum dot) structure. The thesis identifies the material combination for quantum well structure and calculates the absorption coefficient of a MQFl based on quantum well. GaAsSb (barrier)/InAs(dot) was identified as a candidate material for MQFL using quantum dot. The thesis explains the growth mechanism of GaAsSb and the optimization of GaAsSb and GaAs heterointerface. / Dissertation/Thesis / Ph.D. Electrical Engineering 2011

Dans l\'Alcibiade Majeur Socrate dit que «la connaissance de soi» (gnôthi seautón) correspond à la sagesse. Cette connaissance est comprise comme condition essentielle pour la participation dans la vie publique, et est lié au discernement du bien et du mal, elle peut être considéré comme l\'une des conditions pour \"soin de soi\" (epimeleia heautou). Gnôthi seautón se rapporte à un processus de formation. Dans ce travail, nous allons traiter ce processus, particulièrement, de la relation entre les notions de «soin de soi» et «connaissance de soi». Platon estime qu\'il n\'incombe pas aux maîtres de la vertu ou aux dirigeants politiques le rôle formateur. Pas même les rhéteurs, les parents, l\'oracle, les pédagogues compétents peuvent enseigner aux jeunes ce qu\'ils sont réellement. Si un gouvernement de soi est possible, le jeune doit être le sujet. La vertu n\'est pas apprise de la même manière que se donne la transmission d\'un contenu éducatif. Elle ne peut être atteinte d\'une autre manière: à partir d\'un exercice de soi sur soi-même. Ainsi, la véritable fonction du maître de vertu, fonction de Socrate dans les dialogues platoniciens, n\'est pas la transmission du savoir, mais pour convaincre chacun de prendre soin de la vertu, à l\'améliorer. En d\'autres termes, dans l\' Alcibiade, le processus de formation ne consiste pas à la transmission du contenu. L\'éducation résulte de la nouvelle disposition atteinte par l\'interlocuteur par l\'intermédiaire de Socrate. / No Alcibíades Primeiro, Sócrates diz que o conhecimento de si (gnôthi seauton) corresponde à sabedoria. Esse conhecimento é entendido como condição essencial para o engajamento na vida pública, e está ligado ao discernimento do bem e do mal, podendo ser entendido como uma das condições para o cuidado de si(epiméleia heautou). O gnôthi seauton, na filosofia platônica, diz respeito a um processo de formação. Neste trabalho, trataremos desse processo, sobremaneira, a partir da relação entre as noções de cuidado de si e conhecimento de si. Platão entende que não cabe aos mestres de virtude ou aos dirigentes políticos o papel formativo. Nem mesmo os retóricos, os parentes, o oráculo, os pedagogos competentes podem ensinar aos jovens o que eles realmente são. Se um governo de si é possível, o jovem deve ser o sujeito. A virtude não é aprendida da mesma maneira que se dá a transmissão de um conteúdo pedagógico. Ela só pode ser alcançada de outro modo: a partir de um exercício de si sobre si mesmo. Dessa maneira, a verdadeira função do mestre de virtude, função de Sócrates nos diálogos platônicos, não é a transmissão de um saber, e sim convencer cada um a cuidar da virtude, a aperfeiçoar-se. Dito de outro modo, no Primeiro Alcibíades, o processo formativo não consiste na transmissão de um conteúdo. A educação resulta da nova disposição alcançada pelo interlocutor por intermédio de Sócrates.

Despite the suspected biological imprint on the terrestrial silicon (Si) cycle, plant contribution to the Si continental reservoir is poorly quantified. Within the soil-plant system, aqueous silicon (H4SiO40) can be retrieved from soil solution by plant uptake, clay formation and adsorption onto secondary oxides, or leached out and transferred to stream waters. Two approaches are very promising to trace Si within the soil-plant cycle: the Si stable isotopes and Ge/Si ratio. This thesis aims at quantifying the Si isotopic fractionation induced by plants and soil processes in both controlled (in vitro) and natural conditions (in situ). The model used is a tropical soil-plant system involving a Si-accumulating plant (banana, Musa acuminata Colla, cv Grande Naine) cropped on soils derived from basaltic ash but differing in weathering stage (Cameroon, West Africa). Si isotopic compositions in the different compartments of the soil-plant system were measured by MC-ICP-MS in dry plasma mode with external Mg doping. The analytical method required specific developments, and was validated by an inter-laboratory comparison of reference materials. Plant root uptake of Si, and Si transport within the plant induce an isotopic fractionation quantified in vitro and measured in situ. The plant Si isotopic signature is influenced by soil weathering stage, precisely by soil contents of clay and iron oxide. Soil clay-sized fractions sequestrate light Si isotopes following abiotic fractionating processes of mineral weathering and clay formation, leaving a residual solution enriched in heavy Si isotopes. Biogenic Si, enriched in light Si isotopes, constitutes a Si source for clay formation. Clay-sized Fe-oxides concentrate with increasing weathering and soil development. They selectively adsorb light Si isotopes by surface complexation of monomeric H4SiO40. Silicon transport within the plant produces a Ge/Si fractionation involving Ge sequestration in roots whereas weathering and clay formation induce a selective Ge sequestration in clay minerals, producing an increased Ge/Si ratio with increasing weathering, in excellent agreement with Si isotopic data. In the soil-plant system studied, Si stable isotopes thus trace three major continental processes: plant uptake and phytolith formation, sequestration of Si in clay minerals, and adsorption of Si by Fe-oxides. These biotic and abiotic processes all lead to a progressive enrichment of pore waters in heavy Si isotopes.

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Made available in DSpace on 2016-08-29T15:08:22Z (GMT). No. of bitstreams: 1 tese_4542_VITOR HUGO DE OLIVEIRA FIENI.pdf: 1065008 bytes, checksum: b29341af506eed4292347cf30df409d3 (MD5) Previous issue date: 2010-10-26 / Em sua primeira grande obra, a Fenomenologia do Espírito de 1807, Hegel já havia mostrado as razões que fizeram com que a religião fosse tida por ele em tão alta consideração. O fenômeno religioso foi pensado pelo filósofo como um evento através do qual o espírito (Geist) alcança gradualmente o saber de si mesmo como espírito. Isso acontece na medida em que a consciência religiosa tem como seu objeto um Outro que é ela mesma. No entanto, essa igualdade não é clara para esta consciência no início de sua jornada rumo ao Saber Absoluto. O processo de identificação de si consigo mesma vai se traduzir em uma gradual essencialização da imanência e uma imanentização da essência, que acontece ao longo das religiões que Hegel expõe. Neste presente trabalho, faço uma análise da religião manifesta (offenbare Religion) abordada pelo filósofo e de seus momentos, como o lugar onde o saber-de-si do espírito como espírito acontece de modo completo na medida em que o Deus se faz homem e o homem se faz Deus. Mas como essa síntese absoluta não acontece de modo instantâneo, empreendo aqui uma perseguição ao fio dialético que nos conduz a uma deificação do homem e a uma humanização de Deus através da religião natural e da religião da arte, até chegar à figura do Cristo, síntese perfeita entre Deus e o homem. A morte do Messias e a formação da Comunidade cristã, dão o toque final para esse espírito que se torna autoconsciente de si desde si mesmo. Pois, com o sacrifício do Filho de Deus, o seu Si uno com a essência eterna se universaliza àqueles indivíduos participantes da Comunidade e que passam, graças ao Espírito (Santo), a estar em comunhão com a essência eterna. No entanto, a religião não é o último capítulo da Fenomenologia e isso é assim porque, para Hegel, a síntese, a identidade e o saber-de-si do espírito como espírito acontece, na religião manifesta, por meio da representação (Vorstellung). Era, pois, preciso uma reconciliação que fosse mais inteligível e menos sensível: o saber filosófico absoluto. Ou seja, a deificação humana ao lado da antropomorfização divina, feitas religiosamente, não foram suficientes para que a consciência chegasse a seu termo. Em vista disto, empreendo um capítulo crítico final para abordar as consequências humanistas da filosofia hegeliana, onde discuto também um pouco sobre a postura de Hegel com relação àquilo que ele chama de Deus (Gott). Por fim, lanço o conceito de antropo-panteísmo hegeliano como resultado do Saber Absoluto de Hegel.