Submitted by Miguel Henrique Boratto null (miguelhboratto@gmail.com) on 2018-03-24T19:01:03Z No. of bitstreams: 1 M H Boratto - Tese doutorado.pdf: 5163282 bytes, checksum: 63d587fd9642d9da4a7eb0173248c3e9 (MD5) / Approved for entry into archive by Maria Marlene Zaniboni null (zaniboni@bauru.unesp.br) on 2018-03-26T16:38:12Z (GMT) No. of bitstreams: 1 boratto_mh_dr_bauru.pdf: 5163282 bytes, checksum: 63d587fd9642d9da4a7eb0173248c3e9 (MD5) / Made available in DSpace on 2018-03-26T16:38:12Z (GMT). No. of bitstreams: 1 boratto_mh_dr_bauru.pdf: 5163282 bytes, checksum: 63d587fd9642d9da4a7eb0173248c3e9 (MD5) Previous issue date: 2018-02-09 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho compreende o estudo de óxidos semicondutores (Sb:SnO2 e TiO2) e isolantes (ZrO2) obtidos via sol-gel, e a investigação de suas propriedades, de modo a avaliar estes materiais como alternativa para aplicação em dispositivos eletrônicos, tais como Capacitor Metal-Isolante-Metal (MIM), transistores de filmes finos (TFT) e memristores. Os filmes finos de SnO2 foram obtidos através de duas soluções com diferentes tempos de envelhecimento. Os filmes finos de ZrO2 também foram obtidos a partir de duas soluções, produzidas por dois métodos distintos, não-alcoóxido e polimérico. A deposição dos filmes finos foi realizada por dip- e spin-coating, e as caracterizações foram realizadas através das técnicas de DRX, AFM, MEV, Microscopia Confocal, EDX, RBS, TG/DSC, Espectroscopia no espectro UV-Vis, Voltametria Cíclica e Espectroscopia de Impedância, afim de melhor compreender as relações entre propriedades morfológicas e estruturais dos filmes e suas propriedades elétricas. As características de filmes finos de Sb:SnO2 e ZrO2 foram analisadas em dispositivos TFT e MIM, respectivamente. Alternativamente, TiO2 foi acoplado ao Sb:SnO2 e juntos foram aplicados em memristores devido às propriedades elétricas da junção destes semicondutores. Os resultados das análises dos diferentes tipos de dispositivos eletrônicos investigados neste trabalho são discutidos considerando suas diversas características, e são também propostas opções de possíveis melhorias para tais dispositivos tornarem-se comparáveis aos estados-da-arte já existentes. / This work comprises the study of oxide semiconductors (Sb-doped SnO2 and TiO2) and insulating materials (ZrO2) obtained by sol-gel, and the investigation of their properties, aiming to evaluate these materials as alternative for application in electronic devices, such as Metal-Insulator-Metal (MIM) capacitors, Thin Film Transistors (TFT), and Memristors. The SnO2 thin films were obtained by two solutions with different aging times. The ZrO2 thin films were also obtained by two solutions, synthesized from two distinct methods, non-alkoxide and polymeric. The thin film deposition occurred mainly by dip- and spin-coating techniques, and the characterizations were performed through the techniques of XRD, AFM, SEM, Confocal Microscopy, EDX, RBS, TG/DSC, UV-Vis Spectroscopy, cyclic voltammetry and Impedance spectroscopy, in order to better understand the relations between the morphological and structural properties of these films and their electrical properties. The properties of Sb:SnO2 and ZrO2 thin films were analyzed in TFT and MIM devices, respectively. Alternatively TiO2 was coupled with Sb:SnO2 and applied to Memristors due to the electrical properties of this semiconductor junction. The analysis and results of the different devices investigated in this work are discussed considering their several characteristics, and it is also suggested options for possible enhancements for these devices become comparable to existent state-of-the-art devices.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O grupo de materiais ferroelÃtricos com camada de bismuto (BLSFs) tem sido extensivamente estudados, devido à sua potencial utilizaÃÃo em memÃrias de acesso aleatÃrio (aplicaÃÃes FeRAMs). Estruturas perovskita em camadas de bismuto de SrBi2Nb2O9 (SBN) pertencem a famÃlia Aurivillius, que tÃm a fÃrmula geral (Bi2O2)2+(An-1BnO3n+1)2-, onde os sÃtios A sÃo ocupados por cÃtions maiores, enquanto que os cÃtions com elevada valÃncia estÃo localizados em sÃtios B e n à o nÃmero de camadas octaÃdricas entre as camadas de bismuto (Bi2O2)2+. A presenÃa de camadas de bismuto serve como amortecedor para suportar a fadiga da polarizaÃÃo e preservar a estabilidade do bismuto em ferroelÃtricos de camadas estruturadas. Neste trabalho, as propriedades estruturais e dielÃtricas de SrBi2Nb2O9 (SBN) em funÃÃo do nÃvel de adiÃÃo de Bi2O3 ou La2O3 em radiofrequÃncias (RF) e micro-ondas foram estudados. O SBN foi preparado utilizando o mÃtodo de reaÃÃo em estado sÃlido com a adiÃÃo de 3, 5, 10 e 15% de Bi2O3 ou La2O3. A Ãnica fase ortorrÃmbica foi formada apÃs a calcinaÃÃo a 900ÂC durante 2h. A anÃlise por difraÃÃo de Raios X (DRX), utilizando o refinamento de Rietveld confirmou a formaÃÃo de uma Ãnica fase com um composto de estrutura cristalina (a = 5.5129Ã, b = 5,5183à , c = 25,0819Ã; α = β = γ = 90Â). A microscopia eletrÃnica de varredura (MEV) do material mostrou morfologias globulares (quase esfÃrica) de grÃos em toda a superfÃcie das amostras. A temperatura de Curie encontrada para a amostra nÃo dopada foi de 400ÂC. Com adiÃÃes de Bi3+, a temperatura diminuiu e com adiÃÃes de La3+ a temperatura de Curie aumentou significativamente acima de 450ÂC. Nas mediÃÃes das propriedades dielÃtricas de SBN à temperatura ambiente, a 10 MHz, foi observado os maiores valores de permissividade para SBN5LaP (5% de La2O3), com valores de 116,71 e a mais baixa perda (0,0057) foi obtido por SBN15LaP (15% de La2O3). Na regiÃo de frequÃncia de micro-ondas, amostras adicionadas de Bi2O3 mostraram maior permissividade dielÃtrica que amostras adicionadas de La2O3, destacamos a SBN15BiG (15% Bi2O3) com a permissividade dielÃtrica mais elevada em 70,32 (3,4 GHz). Os valores de constante dielÃtrica estÃo compreendidos na faixa de 28-71 e as perdas dielÃtricas sÃo da ordem de 10-2. As amostras foram estudadas para possÃveis aplicaÃÃes em RF e componentes de micro-ondas. / The group of ferroelectric materials with bismuth layer (BLSFs) has been extensively studied due to their potential use in random access memories (FeRAMs applications). Layered structures of perovskite bismuth SrBi2Nb2O9 ( SBN ) belong to the Aurivillius family, which has the general formula (Bi2O2)2+(An-1BnO3n+1)2-, where the sites are occupied by the larger cations, whereas the cations with high valence are located in sites B and n is the number of octahedral layers between the layers of bismuth (Bi2O2)2+. The presence of the bismuth layer serves as a buffer to withstand fatigue and polarization preserving the stability of the bismuth layer structured ferroelectrics. In this work, the structural and dielectric properties of SrBi2Nb2O9 (SBN) based on the level of addition of Bi2O3 or La2O3 on radio frequencies (RF) and microwave were studied. The SBN was prepared using the method of solid state reaction with the addition of 3, 5, 10 and 15% of Bi2O3 and La2O3. A single orthorhombic phase was formed after calcination at 900 C for 2h. The analysis by X-ray diffraction (XRD) using the Rietveld refinement confirmed the formation of a single phase compound with a crystal structure (a = 5.5129Ã, b = 5.5183Ã, c = 25.0819Ã, α = β = γ = 90Â) . The scanning electron microscopy (SEM) showed the material (nearly round) globular grain morphologies across the surface of the samples. The Curie temperature found for the undoped sample was 400ÂC. With additions of Bi3+, and the decreased temperature and with additions of La3+ Curie temperature rose significantly above 450ÂC. In the measurement of the dielectric properties of SBN at room temperature to 10 MHz, the highest values for permittivity SBN5LaP (5% La2O3) were observed, with values of 116.71 and the lowest loss (0.0057) was obtained by SBN15LaP (15% La2O3). In the region of frequency microwave , added Bi2O3 samples showed higher dielectric permittivity that La2O3 samples added, highlight the SBN15BiG (15% Bi2O3) with higher dielectric permittivity in 70.32 (3.4GHz) . The values of dielectric constant are included in the range of 28-71 and the dielectric losses are of the order of 10-2. The samples were investigated for possible applications in RF and microwave components.

Introdução: Nos dias de hoje, possibilitar o acesso à informação com os mais diferentes meios de comunicação torna-se fundamental e ao mesmo tempo desafiador. Deste modo, qualquer estratégia utilizada é importante. A educação a distancia figura como a estratégia facilitadora para o acesso de informação, informação esta que poderá repercutir na qualidade de vida do indivíduo se consideramos, por exemplo, os programas de capacitação com a temática que envolve saúde auditiva. Objetivo: Este estudo teve por objetivo criar uma rede de aprendizagem colaborativa como modelo de educação em saúde auditiva, por meio da Teleducação Interativa e analisar a eficácia do mesmo. Metodologia: o estudo foi realizado em 4 escolas da rede pública da cidade de Bauru. Participaram dessa proposta 38 alunos do 9o ano, de ambos os sexos, na faixa etária entre 14 e 15 anos. O programa de capacitação apresentou duração média de 4 meses em cada escola e foi dividido em 2 etapas, a primeira englobando a elaboração dos módulos educacionais, desenvolvimento do programa de capacitação, atividades presenciais, atividades a distancia e atividades práticas na temática de saúde auditiva e, a segunda etapa consistiu na avaliação da eficácia do programa. Foi desenvolvido o Cybertutor sobre o tema saúde auditiva, com o intuito de complementar o aprendizado, disponibilizado na internet, e os participantes tinham livre acesso. A atividade presencial continha a apresentação de aulas expositivas, conteúdos gráficos e audiovisuais. Na atividade a distância, o conteúdo educacional foi apresentado aos alunos por meio da Teleducação Interativa. Nesta fase, os alunos tiveram acesso ao Cybertutor. Após o período de capacitação, os estudantes intitulados Jovens Doutores, realizaram a atividade prática tendo como proposta a multiplicação do conhecimento adquirido. Para mensurar a eficácia do programa de capacitação foram aplicados os seguintes instrumentos: Questionário Situação-Problema, Escala Lickert de Atitudes Sociais em Relação à inclusão (ELASI) e Ficha de Pesquisa Motivacional (FPM). Resultados: Os resultados das avaliações pré e pós-teste do Questionário Situação-Problema e da ELASI, revelaram que o programa de capacitação desenvolvido foi eficaz, pois proporcionou à construção do conhecimento e o desenvolvimento de atitudes mais favoráveis em relação à inclusão. A FPM demonstrou um índice de motivação em relação à participação altamente positivo, avaliando o programa como Impressionante. Conclusões: O presente estudo permitiu concluir que foi desenvolvido um programa educacional utilizando a Teleducação Interativa como modelo de educação em saúde auditiva. Este programa foi eficaz, pois proporcionou o aprendizado dos alunos das escolas participantes. A elaboração deste modelo de capacitação alcançou um índice de motivação em relação à participação altamente positivo. Mostrou ser uma proposta eficiente de educação na temática sobre a saúde auditiva, podendo ser considerada uma importante estratégia de consolidação da inclusão do deficiente auditivo na comunidade. Na avaliação realizada nas escolas participantes do projeto, a utilização da metodologia do programa Projeto Jovem Doutor estimulou e motivou os participantes a realizarem a multiplicação do conhecimento adquirido, portanto, evidenciou ser um programa eficaz de educação em saúde auditiva, podendo ser utilizado para a capacitação de outras populações. / Introduction: Nowadays, providing access to information with the most different types of media becomes crucial and challenging at the same time. Therefore, any strategy used is important. The distance education appears as a strategy for facilitating access to information, this information that may impact on the quality of life for the individual to consider, for example, programs with the theme that involves hearing health. Objective: This study aimed to create a network of collaborative learning as an educational model for hearing health, tele-education through interactive and analyze the effectiveness of it. Methodology: The study was conducted in four public schools in Bauru. Thirty eight 9th grader students participated in this proposal , both male and female, between 14 and 15 years old. The training program had a mean duration of 4 months in each school and was divided into 2 phases, the first covering the development of educational modules, development of the training program, classroom activities, distance activities and practical activities in the thematic hearing health and the second step was to assess the effectiveness of the program. There was a Cybertutor developed on the hearing health issue, in order to complement the learning available on the Internet, and participants had free access. The classroom activity contained presentation of lectures, graphics and audiovisual content. In the distance learning activity, the educational content was presented to the students through interactive tele-education. At this stage, students had access to Cybertutor. After the training period, the students titled \"Young Doctors\", carried out the practical activity proposing multiplication of the acquired knowledge. To measure the effectiveness of the training program the following instruments were applied: Questionnaire Situation-Problem, Lickert Scale of Social Attitudes Toward Inclusion (ELASI) Form and Motivational Research (FPM). Results: The results of pre-and post-test of the questionnaire Situation- Problem and ELASI revealed that the training program developed was effective because it provided for the construction of knowledge and the development of more favorable attitudes toward inclusion. The FPM showed an index of motivation in relation to highly positive participation, evaluating the program as \"impressive\". Conclusions: This study concluded that an educational program using the Interactive Tele-education as hearing health education model was developed . This program was effective because it provided the learning of students in the participating schools . The development of this training model achieved an index of motivation in relation to highly positive participation. It is an efficient education proposal on the issue about hearing health and may be considered an important strategy to consolidate the inclusion of the hearing impaired community. In the evaluation of the project in the participating schools, the use of the methodology of program design Young Doctor stimulated and motivated the participants to perform the multiplication of the knowledge acquired thus proven to be an effective program of health education and can be used for training other populations.

Este trabalho apresenta a compensação e calibração de sensores de pressão piezoresistivos com a utilização de resistores de alta precisão. Para que tal objetivo fosse cumprido, foi necessária a caracterização do sensor com relação aos parâmetros térmicos e elétricos. Além disso, foi definida uma metodologia com a qual se obteve os tempos necessários para aquisição dos dados com relação ao valor de precisão requisitada. Os resultados mostram que os valores dos resistores são dependentes da alimentação fornecida ao sensor e que a variação da tensão de saída, com relação a uma média, tem caráter parabólico. A curva do tempo de estabilização para aquisição de dados tem formato assintótico. Com a compensação e calibração tivemos uma diminuição na tensão de offset de cerca de 97% e compensação térmica com cerca de 70% para a tensão de fundo de escala, porém com isso foi reduzido 8% no valor da sensibilidade. / This work presents the compensation and calibration of piezoresistive pressure sensors with the use of precision resistors. For this objective to be met was necessary to characterize the sensor with respect to thermal and electrical parameters. Also it was defined a methodology with which they obtained the time required for data acquisition based on the value of precision required. The results show that the values of resistors are dependent on power supplied to the sensor and the variation of the output voltage with respect to an average has a parabolic feature. The curve of the settling time for data acquisition format is asymptotic. With the compensation and calibration, a decrease in the offset voltage of about 97% was observed and temperature was compensated with 70% for full scale, however, the sensitivity was reduced in 8%.

Nanomaterials have been served as essential building blocks in the era of nanotechnology. Nanomaterials often exhibit different properties compared to their bulk phase, due to heavily enlarged portion of surface characteristics to the bulk. Beyond the simple size- effect, nanomaterials can be classified into 0D, 1D, and 2D materials depends on the number of restricted dimensionalities. They exhibit different unique properties and transport mechanism due to the quantum confinement effect. MXenes are one of the latest additions of 2D material family that can be obtained by selective chemical etching and exfoliation of layered ternary precursors (Mn+1AXn phases). Due to the unique etch process, surface functional groups (such as oxygen, hydroxyl, fluorine, etc) are formed at the surface of MXenes. This benefits MXenes for stable aqueous dispersions due to their hydrophilic surface. The coexistence of hydrophilicity and high electrical conductivity promised MXenes in superior performance in electrochemical energy storage and electromagnetic interference shielding applications. These characteristics are equally important for electronic applications. From the synthesis of MXene suspension to thin film deposition by spray-coating and photolithography patterning of MXene films are discussed for electronic device applications of MXenes. Vacuum-assisted filtration method was used for Mo-based MXene freestanding papers for investigation of thermoelectric energy harvesting performances. Both n-type ZnO and p-type SnO thin film transistors with MXene electrical contacts (gate, source, and drain electrodes) have been demonstrated by lift-off patterning method. Their complementary metal-oxide-semiconductor (CMOS) inverter exhibits a high gain value of 80 V/V at a supply voltage of 5 V. The lift-off patterning is simple but effective method for top-contact electrode patterning. However, it has a disadvantage of remaining sidewall-like MXene residue, resulting in leakage issues in the bottom-contact transistor structure. Hence, dry-etch patterning method is developed which allows direct patterning of MXene nanosheet thin films through conventional photolithography process. The conductive MXene electrode array was integrated into a quantum dot electric double layer transistors by all solution processes, which possess impressive performance including electron mobility of 3.3 cm2/V·s, current modulation of 104, threshold voltage as low as 0.36 V at low driving gate voltage range of only 1.25 V.

With the increasing interest in wide-band gap devices, their potential benefits in power applications have been studied and explored with numerous studies conducted for both SiC and GaN devices. This thesis investigates the use of wide-band gap devices as the switching element in a semiconductor DC breaker. It involves the design of an efficient semiconductor DC breaker, its simulation in SPICE, construction of a hardware prototype and the comparative study of SiC and Si versions of the aforementioned breaker. The results obtained from the experiments conducted in the process of concluding this thesis show that the SiC version of the breaker is a superior option for a semiconductor DC breaker.

Due to the growth of wireless communication many communication frequencies have grown increasingly dense. This density requires higher Q-factor to receive only the signal of interest. With the rise of smaller integrated circuits previous solutions used for filtering have become viable again. This paper explores whether the N-path filter is viable in the modern day for radio frequency receiver purposes. A non-differential N-path filter was created by utilizing Cadence Virtuoso with a working center frequency range of 750MHz to 1GHz while using TSMC technology. The desired quality factor of over 1,000 was reached while maintaining a total area of 800 by 800 micrometers. Through the analysis of the N-path filter new techniques for mixed signal analysis were used for simulation. This included parametric analysis in Cadence ADE-L and additional analysis in MATLAB, and the addition of a bootstrapping circuit to decrease simulation time. Future applications regarding analyzing mixed signals could use these methods to provide frequency response data and automated processing.

The objective and motivation for this project is to design a low-power, low-noise oven-control circuit to optimize the stability of a MEMS oscillator. MEMS oscillators can be fabricated using conventional semiconductor manufacturing methods and can often be assembled in packages smaller than those of traditional crystal oscillators. However, one of their largest disadvantages currently is their high temperature coefficient of frequency (TCF), causing MEMS oscillators to be especially sensitive to temperature changes. Hence, this project focuses on designing a printed circuit board that will allow the user to manually tune a current passing through a resonator wire-bonded to the board to elevate the resonator temperature. This will ensure that the device's resonance frequency stays largely constant and that the oscillator provides a very stable signal.

Terahertz region in the electromagnetic spectrum is the region between Infrared and Microwave. As the Terahertz region has both wave and particle nature, it is difficult to make a room temperature, fast, and sensitive detector in this region. In this work, we fabricated a Palladium based IR detector and a CNT based THz bolometer. In Chapter 1, I give a brief introduction of the Terahertz region, the detectors already available in the market and different techniques I can use to test my detector. In Chapter 2, I explain about the Palladium IR bolometer, the fabrication technique I have used, and then we discuss the performance of the detector. In Chapter 3, I explained about the Roll to Roll based THz bolometer, its working and fabrication techniques, and at the end we discussed its performance.

<p>Metamorphic buffer (MB) layers were studied as a means to grow epilayers on top of a GaAs substrate which have different lattice constant than the GaAs. Growths were done by molecular beam epitaxy on a GaAs (001) substrate. The growths of step-graded InGaAs and InGaAsP MBs have been investigated using both linear and logarithmic grading profiles. The logarithmic grading profile shows slight improvement in the crystal quality over the linear grading profiles. This is an indication that instead of increasing the strain with the same grading rate, it may be helpful to have higher grading rate at the beginning and lower grading rate at the end of the buffer. InGaAsP graded buffers were grown where group III ratio was kept fixed. However due to the existence of phase separation and lower relaxation the quaternary growths exhibited no performance improvement as might have been expected from growths with only group V grading. Also, the effects of using an InGaP layer grown at low temperature before the MB were determined. Quantum wells (QW), which were grown on top of the MBs, were used to probe the optical emission properties. No significant difference was observed in photoluminescence between the samples with a low temperature layer and without a low temperature layer. Annealing enhanced the PL intensity but the crystal quality degraded due to the appearance of surface defects. Surface undulations, known as “cross-hatch” (CH), were observed in the top MB layers. Atomic force microscopy (AFM) was used to analyze the surface morphology and degree of polarization (DOP) measurement was used to analyze the strain features in the final MB layer. Similar patterns of both surface morphology and strain field indicate a correlation between these two. From analysis of the periodicity of strain field and the CH, evidence was found in the support of one of the existing models of CH evolution which implies that the CH appears before the formation of MDs and subsequently MDs form at some troughs in the undulation.</p> / Master of Applied Science (MASc)