Orientador: Ivo Milton Raimundo Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T08:19:59Z (GMT). No. of bitstreams: 1 Fernandes_RafaeldaSilva_M.pdf: 4434291 bytes, checksum: 9e165eb303705fd4708d721442efb456 (MD5) Previous issue date: 2014 / Resumo: Neste trabalho foram desenvolvidos nanossensores fluorescentes reutilizáveis para determinação de íons Cu(II) através do encapsulamento da rodamina B em nanopartículas de sílica (NPSRB ¿ 5), sintetizadas com base no método de Stöber. Objetivando identificar, compreender e, consequentemente, controlar todos os parâmetros envolvidos na síntese, foram realizados estudos uni e multivariado. No estudo univariado foram avaliados os efeitos da temperatura, velocidade de agitação, concentração do catalisador (hidróxido de amônio), concentração de água, razão molar [água] / [TEOS] e [etanol] / [TEOS]. No estudo multivariado foram avaliados os efeitos da água, TEOS, etanol e hidróxido de amônio. Os resultados do estudo univariado mostraram que todos os parâmetros estudados apresentaram influência no tamanho e morfologia das nanopartículas. No estudo multivariado foi possível identificar que as variáveis envolvidas na síntese apresentam tais efeitos somente em condições específicas. Após a identificação e, consequentemente, um maior controle dos parâmetros envolvidos na síntese de nanopartículas, iniciou-se o desenvolvimento dos nanossensores fluorescentes reutilizáveis. Neste trabalho dois nanossensores foram desenvolvidos com concentração do catalisador (NH3) de 0,18 mol L-1 para o nanossensor 1, e 0,70 mol L-1 para o nanossensor 2. O nanossensor 2, produzido em uma síntese de 2 h, não apresentou resposta a íons Cu(II) (supressão de fluorescência), isso porque as nanopartículas não possuíam porosidade, o que impediu o acesso dos íons Cu(II) à rodamina. O nanossensor 1, desenvolvido em uma síntese de 7 h, apresentou resposta a íons Cu(II). O reagente luminescente foi adicionado em diferentes estágios da síntese (2, 3, 4 e 5 h), onde o nanossensor com a adição da rodamina B em 5 h de síntese apresentou os melhores resultados. O nanossensor apresentou faixa linear entre 2,0 ¿ 12,0 µmol L-1, limite de detecção de 0,40 µmol L-1, limite de quantificação de 1,3 µmol L-1, tempo de resposta de 50 s e seletivo a íons Cu(II) podendo ser reutilizado 3 vezes. O nanossensor foi aplicado na determinação de íons Cu(II) em cachaça, produzindo resultados que não diferiram significativamente ao nível de confiança de 95 % dos resultados obtidos por espectrometria de absorção atômica / Abstract: In this work, a reusable fluorescent nanosensor for determination of Cu(II) ions was developed by encapsulating rhodamine B in silica nanoparticles synthesized based on Stöber method. In preliminary studies, it was possible to identify a relationship between the performance of nanossensor and the properties of the silica nanoparticles. In order to identify, understand and thus control all the parameters involved in the synthesis, univariate and multivariate studies were performed. In the univariate study, it was evaluated the effect of temperature, stirring speed, catalyst concentration (ammonium hydroxide), water concentration, and [water] / [TEOS] and [ethanol] / [TEOS] molar ratios. In the multivariate study, it was evaluated the effect of water, TEOS, ethanol and ammonium hydroxide. Results obtained in the univariate study showed that all parameters affect the size and the morphology of the nanoparticles. In the multivariate study, it was found that the variables involved in the synthesis have such effects only under specific conditions. After identification and, consequently, better control of the parameters involved in the synthesis of nanoparticles, the development of fluorescent nanosensors was carried out. Two nanosensors were developed, synthesized with catalyst concentration (NH3) of 0.18 mol L-1 for the nanosensor 1, and 0.70 mol L-1 for the nanosensor 2. The nanosensor 2, developed in a synthesis of 2 h, did not present response to Cu(II) ions (fluorescence quenching), because nanoparticles did not present porosity, which prevented the access of Cu(II) ion to rhodamine. The nanosensor 1, developed in a synthesis of 7 h, showed response to Cu(II) ions. The luminescent reagent was added at different stages of the synthesis (2, 3, 4 and 5 hours), and the nanosensor obtained with addition of rhodamine B after 5 h of synthesis showed the best results. The nanosensor showed linear range from 2.0 to 12.0 µmol L-1, detection limit of 0.40 µmol L-1, quantification limit of 1.3 µmol L-1, response time of 50 s and selectivity to Cu(II) ions which can be reused 3 times. The nanosensor was applied to the determination of Cu(II) in sugar cane spirit and the results obtained did not show significant differences from those obtained by atomic absorption spectrometry at a confidence level of 95 % / Mestrado / Quimica Analitica / Mestre em Química

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Outputs of human-derived chemicals and constituents to the environment, and shifts in these outputs, can result in unintended consequences to human and ecological health. One such shift is the advent of the modern antibiotic era, in which mass production and outputs of antibiotics, which are mostly naturally-derived microbial defense compounds and include a few synthetic antimicrobials, has profound implications for contributing to the spread of antibiotic resistance. Antibiotic resistance arises from mutations and/or sharing of antibiotic resistance genes (ARGs) among bacteria via horizontal gene transfer, with carriage of ARGs by pathogenic bacteria of particular concern to human health. While most attention to stopping the spread of antibiotic resistance has been devoted to the clinic, it is critical to consider the environmental origin, ecology and pathways by which antibiotic resistance spreads in order to develop comprehensive strategies to combat antibiotic resistance. In particular, wastewater treatment plants (WWTPs) represent a potentially key critical control point given that they receive antibiotic resistant bacteria (ARB) and ARGs from the population, which are then routed to activated sludge biological treatment, consisting of high density, highly active microbial populations. The research projects described in this dissertation aimed to explore the occurrence of ARGs in WWTPs, particularly WWTPs in developing countries representing the extremes of what is expected to be encountered in terms of potential to spread antibiotic resistance, and to improve and apply novel technologies for monitoring key markers of antibiotic resistance in WWTPs and affected environments. The pathogen Staphylococcus aureus and a corresponding ARG (methicillin resistance mecA gene) were chosen as model biocontaminants of concern due to their environmental and public health relevance. The results reported in Chapters 3-5 advance the knowledge of bio(nano)sensing techniques and highlight areas of promise and challenge. The results reported in Chapter 2 provided insight into the baseline levels of ARGs expected in a highly impacted WWTP in India, thereby highlighting the magnitude and global scale of the problem of antibiotic resistance as well as the need for innovative solutions. / Ph. D.

Cette thèse décrit la réalisation d’un nanocalorimètre dynamique différentiel pour l’étude de la transition vitreuse. Le capteur microfabriqué, la chaine de mesure de bas niveau de bruit et de grande stabilité, ainsi que l’environnement thermique du capteur sont décrits en détails. La méthode de mesure utilisée est une méthode fréquentielle dans laquelle l’amplitude et la phase de la température oscillante sont mesurées avec une grande résolution. La résolution du nanocalorimètre sur le module de la capacité calorifique complexe est de ∆|C_p^* |/|C_p^* |  ± 0,001 %, et sur la phase de l’oscillation de température est de ∆φ/φ  ± 0,0005 %. La résolution est environ mille fois plus élevée que celle des calorimètres à modulation de température commerciaux. Les potentialités du nanocalorimètre pour l’étude d’effets thermodynamiques et cinétiques fins sont démontrées sur un modèle de polymère vitreux, le poly(acétate de vinyle). Des effets nouveaux et trop tenus pour être détectés avec des calorimètres classiques ont été mesurés. Le module de la capacité calorifique complexe et la phase de l’oscillation de température présentent des relaxations temporelles de faible variation dans l’état de liquide surfondu comme dans l’état vitreux. De plus, le dégel des degrés de libertés internes structuraux du polymère peut, suivant l’histoire thermique suivie par le matériau, se réaliser en deux étapes lors du réchauffement. Ce double dégel n’est visible que sur la dérivée en température du module de la capacité calorifique complexe. En conclusion, la résolution, la stabilité et la répétabilité du nanocalorimètre sont particulièrement adaptées à des mesures nanocalorimétriques fines pour l’étude thermodynamique et cinétique de systèmes complexes hors équilibres dont les verres font partie. / This thesis reports the working principle and the building up of a dynamic differential nanocalorimeter to the study of the glass transition. The micro-fabricated sensor, the low noise and highly stable measurement chain, as well as the thermal environment of the sensor are described in details. The measurement method is a spectroscopic method in which the amplitude and phase of the oscillating temperature are measured with a high resolution at different frequencies. The resolution of the nanocalorimeter on the measurement of the complex heat capacity module is ∆|C_p^* |/|C_p^* |  ± 0,001 %, and on the phase of the temperature oscillation is ∆φ/φ  ± 0, 0005 %. This resolution is about one thousand times higher than that of the commercial temperature modulated calorimeters. The potentialities of the nanocalorimeter for the study of fine thermodynamic and kinetic effects are demonstrated on a model of glassy polymer, the poly(vinyl acetate). New effects which are too fine to be detected by conventional calorimeters have been measured. The modulus of the complex heat capacity and the phase of the temperature oscillation exhibit small relaxational effects of low amplitude either in the super-cooled liquid state or in the glassy state. In addition, according to the thermal history followed by the material, the structural recovery of this polymer can take place in two steps during the heating. These two steps are visible only on the temperature derivative of the modulus of the complex heat capacity. In conclusion, resolution, stability and repeatability of the nanocalorimeter are particularly suitable for fine thermodynamic and kinetic study on out of equilibrium complex systems such as glasses.

Made available in DSpace on 2016-06-02T19:02:41Z (GMT). No. of bitstreams: 1 4784.pdf: 6177335 bytes, checksum: d4efe41cda16378eef382581c4b2c468 (MD5) Previous issue date: 2012-05-31 / Universidade Federal de Minas Gerais / The great interest to develop microcantilevers sensors is due to several desirable properties, in particular the ability to adjust the size and structure, thus increasing the perspectives for the construction of new sensor systems. In this work, we developed functionalized microcantilever sensors with conducting polymers to detect relative humidity, volatile organic compounds and insect pheromones. The development was based on a systematic investigation, since the polymer synthesis and the film formation until the sensing step. For this purpose, we studied two treatments to clean the microcantilevers surfaces (plasma and piranha solution). Also, appropriate ways for the sensors functionalization were evaluated, using spin-coating and thermoelastic probe techniques. The polyaniline solutions were obtained by the in-situ and interfacial synthesis. This way, the doping, morphology and the polymer structure have been investigated by the AFM, UV-Vis, FTIR, diffraction and FE-SEM techniques, and likewise the film properties. It allowed us to optimize the preparation conditions of the polyaniline films on the surface of the microcantilevers sensors to detect relative humidity and volatiles. Also, it was possible to develop sensors with polyaniline thin films, capable to detect 1 ppmv of relative humidity, and this shows that they can be used to measure large limits of detection. Moreover, the functionalized microcantilevers sensors showed a fast response time, repeatability over several cycles and exhibited lifetime longer than 6 months. The coated microcantilevers sensors showed an excellent response to the volatile organic compounds (VOCs), indicating that the sensitive layer was xiv appropriate for detection of these volatiles. The sensitivity of these sensors at VOCs increased with the polarity, thus the methanol compound showed the greatest sensitivity. It was possible to detect and evaluate different concentrations of the pheromone 2-heptanone, at different temperatures. The microcantilever sensors response not only showed an excellent sensitivity, but also a fast response time. It was observed an excellent response to deflection of the microcantilever sensors when exposed to volatile during the banana ripeness. / O grande interesse em desenvolver sensores de microcantilevers é devido às várias propriedades desejáveis, em particular a capacidade de adaptar o tamanho e a estrutura, aumentando, dessa forma, as perspectivas para a construção de novos sistemas de sensoriamento. Neste trabalho foram desenvolvidos nanossensores de microcantilever funcionalizados com polianilina, no estado de oxidação esmeraldina, para detecção de umidade relativa, de compostos orgânicos voláteis e, potenciais aplicações para detecção de feromônios de insetos e no amadurecimento de frutas. Para isso, o desenvolvimento se baseou em uma investigação sistemática, desde a síntese do polímero e a formação de filmes até a etapa de sensoriamento. Para tal, foram estudados dois tratamentos de limpeza das superfícies dos microcantilevers, o plasma e a solução piranha . Também foram avaliadas maneiras adequadas para a funcionalização dos sensores, empregando as técnicas de spin-coating, in-situ e sonda termoelástica à partir de soluções de polianilina obtidas pelas sínteses interfacial e in-situ, para a deposição de um filme fino em somente um lado da superfície do microcantilever. Dessa forma, a dopagem, cristalinidade e estrutura do polímero foram investigadas por meio das técnicas de UV-Vis, FTIR, difratometria e FE-MEV e, por conseguinte, as propriedades dos filmes. Estes estudos permitiram aperfeiçoar as condições de preparação dos filmes de polianilina sobre a superfície dos sensores de microcantilevers, para detecção de umidade relativa (%) e compostos orgânicos voláteis (COVs). Foi possível desenvolver sensores com filmes finos de polianilina, capazes de detectar umidade relativa até 1 ppmv, indicando, portanto, que os sensores xii desenvolvidos podem ser usados para medir grandes limites de detecção. Além disso, os sensores de microcantilevers funcionalizados apresentaram um tempo de resposta rápido, foram repetitivos a vários ciclos e apresentaram uma durabilidade maior que 6 meses. Os sensores de microcantilevers funcionalizados apresentaram uma excelente reposta aos COVs, indicando que a camada sensitiva foi adequada para detecção desses voláteis. A sensitividade dos sensores de microcantilever funcionalizados aos COVs aumentou com o aumento da polaridade do volátil, assim o composto que apresentou maior sensitividade foi o metanol. Foi possível avaliar e detectar diferentes concentrações do feromônio 2- heptanona em diferentes temperaturas. Os sensores mostraram uma excelente sensitividade e um tempo de resposta rápido. Foi observada uma excelente resposta de deflexão dos sensores de microcantilever quando expostos aos voláteis, durante o amadurecimento da banana.

Made available in DSpace on 2018-06-27T18:56:13Z (GMT). No. of bitstreams: 3 Rochele Cristine Aymay Bevilaqua.pdf: 4584354 bytes, checksum: 395258de907af3f78f22cdd57483ea53 (MD5) Rochele Cristine Aymay Bevilaqua.pdf.txt: 183116 bytes, checksum: 85dded0e1a86682707a6ccf16e494abd (MD5) Rochele Cristine Aymay Bevilaqua.pdf.jpg: 3219 bytes, checksum: b175371ca0df47f8e821438052396b10 (MD5) Previous issue date: 2010-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work, we study nanostructures through first principles calculations based on the Density Functional Theory to use as gas sensors. At first, the proposal is based on the study of carbon nanotubes filled with iron oxides, particularly hematite and magnetite, for interaction with O2, N2 and CO2. Based on the analysis of electronic properties of semiconductors tubes with different diameters SWNT (8,0), (10,0) e (13,0) is verified that gases cause changes in al cases, making them as potential candidates to detect gases on the environment. In addition to these carbon-based nanostructures to serve as nanosensores, a second proposal was raised: the use of biomolecules as gas sensor. We chose the chlorophyll a and pheophytin a (a derivative without a magnesium atom in its structure) as an economically favorable alternative due to its low cost and easy to obtain. In fact, these pigments proved to be good sensor devices because the modest binding energy (-0.20 eV to -0.13 eV chlorophyll a to pheophytin a) that indicate a physical interaction with the gases O2, N2 and CO2. So it s possible to say that we can use both of systems carbon nanotubos filled iron oxides and chlorophyll a and its derivative as filters or gas sensors since the removal of gases from these nanostructures can occur easily making them reusable. / Nesta dissertação, estudaram-se nanoestruturas para sensoriamento de gases por meio de cálculos de primeiros princípios baseados na Teoria do Funcional da Densidade. Primeiramente, a proposta se baseia no estudo de nanotubos de carbono preenchidos com óxidos de ferro, em particular a hematita e a magnetita, para interação com O2, N2 e CO2. Em todos os sistemas estudados utilizaram-se tubos semicondutores de diferentes diâmetros. Através da análise de propriedades eletrônicas, verificou-se que os gases ocasionam alterações nos nanotubos de carbono, tornado-os potenciais candidatos para detecção de gases no meio ambiente. Além dessas nanoestruturas baseadas em carbono para servir como nanosensores, uma segunda proposta foi levantada: a utilização de biomoléculas. Optou-se, então, pelo uso de porfirinas, em especial pela clorofila a e a feofitina a, como uma alternativa economicamente favorável devido ao seu baixo custo e fácil obtenção. De fato, esses pigmentos apresentaram-se como bons dispositivos sensores em razão das energias de ligação (-0,20 eV para a clorofila a e -0,13 eV para a feofitina a) que indicam uma interação física com os gases O2, N2 e CO2. Portanto, os resultados obtidos sugerem que essas nanoestruturas nanotubos de carbono preenchidos com óxidos de ferro e a clorofila a e seu derivado podem ser utilizadas como nanosensores efetivos de gases uma vez que a detecção dessas moléculas pode ser facilmente efetuada sem prejudicar a reutilização desses sistemas.

Recent improvements in sensor technology and applications can be partly attributed to the advancements in microand nanoscale fabrication processes and discovery of novel materials. The emergence of reliable and inexpensive methods of production of monolayer materials, such as graphene, has revealed the advantageous electronic properties which when utilized in sensory elements can significantly enhance response to the input signal. Hence, graphene-based sensory devices have been widely investigated as the exotic properties of the carbon nanomaterial allow for cost-efficient scalable production of highly sensitive transduction elements. Previous studies have shown successful detection of n-type dopants such as ammonia and low pH solution. As the amine group in amphetamine molecules is known to behave as an electron donor, in this study, graphene conductivity changes in response to exposure to amphetamine salt solutions were investigated.Graphene formed by chemical vapour deposition (CVD) was transferred onto SiO2 substrate with gold electrodes to form a resistive transducer. Observation of large intensity ratio of graphene characteristic 2D and G peaks as well as minimal defect peaks from Raman spectroscopy analysis proved the integrity of the carbon monolayer was maintained. The atomic force microscopy and resistance measurements results showed the storage of these sensory elements in ambient conditions results in adsorption of impurities which considerably influence the electronic properties of graphene. Upon exposure to amphetamine sulfate and amphetamine hydrochloride, conductivity decrease was detected as expected. Signal enhancement by excitation of 470nm light did not show a significant increase in response magnitude. However, the low reliability of sensor response limited further analysis of the chemical sensor signal. Non-selective sensor response to amphetamine can be detected, but improvements in device design are needed to minimize contamination of the graphene surface by ambient impurities and variations in the sensor system. / De senaste förbättringarna i sensorteknik och applikationer kan kopplas till framsteg inom framställningsprocesser berörande mikrooch nanoskala samt upptäckt av nya material. Framväxten av tillförlitliga och billiga produktionsmetoder av monoskiktmaterial, såsom grafen, har avslöjat de fördelaktiga elektroniska egenskaperna som när de används i sensoriska element och förbättrar signalresponsen till inputsignalen. Grafenbaserade sensoriska applicationer har undersökts allteftersom de exotiska egenskaperna hos kolbaserade nanomaterial möjliggör en kostnadseffektiv skalbara produktion av högkänsliga transduktionselement. Tidigare studier har framgångsrikt visat detektion av n-typ substanser såsom ammoniak och låg pH-lösning. Eftersom amingruppen i amfetaminmolekyler är känd för att verka som en elektrondonator, undersöktes i denna studie konduktivitetsändringar i grafen under exponering för amfetaminsaltlösningar.Grafen bildad genom kemisk ångavsättning (CVD) överfördes på Si02-substrat med guldelektroder för att bilda en resistiv omvandlare. Observation av intensitetförhållandet mellan de grafenkarakteristiska 2Doch G-topparna samt minimala defekttoppar från Ramanspektroskopianalysen visade att kolmonolagrets struktur upprätthölls. Resultaten av atomkraftmikroskopi och resistansmätningar visade att lagringen av de sensoriska element i normala omgivningsförhållanden resulterar i adsorption av föroreningar som avsevärt påverkar grafens elektroniska egenskaper. Vid exponering för amfetaminsulfat och amfetaminhydroklorid upptäcktes en förväntad konduktivitetsminskning. Signalförbättring genom excitation av 470nm-ljus visade inte en signifikant ökning av svarstyrkan. Den låga tillförlitligheten hos sensorn begränsade emellertid ytterligare analys av den kemiska sensorsignalen. Sensorns icke-selektiva svar på amfetamin kan detekteras, men förbättringar i enhetens konstruktion behövs för att minimera kontaminering av omgivande föroreningar på grafenytan och variationer i sensorsystemet.

anks to their unique properties and high biocompatibilities, fluorescent nanodiamonds are promising representatives of modern carbon nanomaterials with a broad range of applications. Nevertheless, their wider use is limited because of weak fluorescence intensity and low colloidal stability in the biological environment. e optimization of treatment procedures and development of new suitable surface designs is therefore critically needed. In this study, several key steps for fluorescent nanodiamond treatment have been optimized, leading to both a substantial increase in fluorescence intensity and to significantly lower surface damage caused by graphitization. Further, a new high-throughput irradiation technique was developed. e influence of surface chemistry on the fluorescence parameters was studied using partial fluorination of the functional groups on the nanodiamond surface. A novel method which significantly affects the interaction of nanodiamonds with biological systems by increasing of the homogeneity and circularity was developed. e potential of nanodiamonds for future medical and biological research was demonstrated on particles with complex surface architectures that enabled targeting and therapy of tumor cells. Moreover, a strong and highly selective affinity of fibroblast growth factors to diamond...

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Orientador: Mônica Alonso Cotta / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-17T22:17:37Z (GMT). No. of bitstreams: 1 NietoGonzalez_Luis_D.pdf: 3428571 bytes, checksum: 13775c720d8ebcf8c855b532ae715b49 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho estudamos os mecanismos de crescimento durante a epitaxia por feixe químico de nanoestruturas III-V baseadas no sistema InAs/InP. Particularmente, foram estudados nanofios e ilhas de InAs sobre uma camada buffer InP(001) e nanofios de InAs sobre uma matriz de InGaAs/InP (com mesmo parâmetro de rede). Apresentaremos, nesta tese, as diferenças e similaridades destes sistemas quanto a condições de crescimento, distribuição de tamanho, forma e os efeitos de volume da camada de InGaAs sobre as nanoestruturas de InAs quando comparadas ao sistema InAs/InP. Nossa escolha do InGaAs/InP como camada buffer para a nucleação dos fios de InAs, foi feita porque facilitaria a utilização deste sistema em diversas aplicações, proporcionando maior flexibilidade no desenho dos dispositivos. Por outro lado, este material abre a possibilidade de controlar as características das nanoestruturas através das propriedades de bulk e superficiais da liga ternária InGaAs. Além disso, ligas ternárias podem exibir efeitos de volume que afetam suas propriedades superficiais. Estes fenômenos podem afetar a nucleação dos fios quânticos e por isso foram objeto de nosso estudo. Para isso utilizamos e correlacionamos medidas in situ de difração de elétrons de alta energia (RHEED), microscopia de força atômica (AFM) e eletrônica de transmissão (TEM), com os resultados obtidos por difração de raios X com incidência rasante (GIXD). Verificamos, deste modo, tanto a influência das condições de crescimento, como o comportamento da relaxação da energia elástica nas nanoestruturas. Com todos estes resultados mostramos como acontece a evolução da deformação nos nanofios e pontos quânticos de InAs/InP e como acontecem as transições de forma entre estes dois tipos de nanoestruturas, em função das condições de crescimento e tipo de superfície do substrato utilizado. Mostramos, também que a introdução de um composto ternário (InGaAs) entre o InAs e o InP não afeta significativamente a forma e tamanho das nanoestruturas quando comparadas ao caso InAs/InP. Em particular, a interdifusão gerada por variações locais da composição na camada buffer em nanofios de InAs pode ser minimizada através de mudanças nas condições de crescimento do InGaAs / Abstract: In this work we study the growth mechanisms of III-V nanostructures by chemical beam epitaxy (CBE) based on the InAs/InP materials system. Particularly, nanowires and nanodots of InAs on InP (001) and InAs nanowires on InGaAs/InP (lattice matched) buffer layers were studied. The differences and similarities of these systems are presented in this text, as a function of growth conditions, size distribution, as well as the bulk effects of the InGaAs layer on InAs nanostructures when compared to the InAs/InP system. Our choice of InGaAs/InP buffer layer for InAs nanowire nucleation was due to the possible use of this system in many applications, providing greater flexibility in device design. Furthermore, this material opens up the possibility of controlling nanostructures characteristics through bulk and surface properties of the InGaAs ternary alloy. In other hand, ternary alloys may present volume effects that affect their surface properties. These phenomena can affect quantum wires nucleation and thus became one of the subjects of our study. With these goals in mind, we have correlated in situ high-energy electrons diffraction (RHEED) measurements, atomic force microscopy (AFM) and transmission electron microscopy (TEM) images with the results obtained by grazing incidence X-ray diffraction (GIXD). We report here the influence of the growth conditions on nanostructure shape as well as the behavior of elastic energy relaxation within the nanostructures. Our results show how the evolution of deformation within InAs/InP nanowires and quantum dots occur and how the shape transition between these two types of nanostructures depend on the growth conditions and the substrate surface type used. We also show that the introduction of a ternary compound (InGaAs) between InAs and InP does not significantly affect the shape and size of nanostructures as compared to the InAs / InP case. In particular, the interdifusion generated in InAs nanowires by local variations in the buffer layer composition can be minimized through changes in InGaAs growth conditions / Doutorado / Estrutura de Líquidos e Sólidos; Cristalografia / Doutor em Ciências