Crescimento de cristais nanoestruturados baseados em óxidos de antimônio
Data
2019-12-18
Autores
Barros, Herick Ematne da Silva
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Neste trabalho foram desenvolvidas rotas de crescimento de micro- e nanoestruturas de Sb2O3 e Sb2O4 através de métodos de deposição de fase vapor. Para análise das amostras obtidas foram utilizadas técnicas de difratometria de raios-X, microscopia eletrônica de varredura e espectroscopia Raman. A análise dos resultados obtidos permitiu identificar corretamente as algumas das características estruturais e morfológicas das amostras bem como definir uma rota de crescimento de qualidade e reprodutibilidade. Após a produção e caracterização das amostras dos óxidos de antimônio foi feita a funcionalização e decoração superficial das nanoestruturas de Sb2O3 com nanopartículas de paládio. As nanoestruturas funcionalizadas foram devidamente caracterizadas pelas mesmas técnicas aplicadas as amostras puras dos óxidos, com isso foi possível verificar a eficácia do processo de decoração superficial bem como obter informações sobre a estrutura do produto final desse processo. A síntese de Sb2O3 gerou amostras com 3 tipos de morfologias diferentes, a primeira possui fase cristalina ortorrômbica e consiste de micro e nanofitas ramificadas, as outras duas morfologias são constituídas por seguimentos de micro octaedros empilhados e aglomerados de micrestruturas octaédricas e microesferas, ambas apresentam fase cristalina cúbica. O processo de decoração superficial das amostras de Sb2O3 com nanopartículas de paládio se mostrou eficaz, porém levou a uma grande alteração na morfologia das amostras de Sb2O3. A síntese das amostras de Sb2O4 produziu micro- e nanofios misturados à micro-fitas ramificadas, ambas as morfologias apresentam fase cristalina ortorrômbica
In this work, Sb2O3 and Sb2O4 micro- and nanostructures were synthesized by a vapor phase deposition method. Aiming to provide data on the structure of these samples, Xray diffraction, scanning electron microscopy and Raman spectroscopy techniques were used. The data analysis allowed to correctly identify the characteristics of the samples as well as to define a good and reproductible growth process. The as-grown Sb2O3 was submitted to palladium nanoparticles functionalization and superficial decoration process. The functionalized nanostructures were duly characterized by the same techniques applied to the pure oxide samples, with the purpose of verifying the effectiveness of the surface decoration process as well as obtaining information on the structure. The Sb2O3 synthesis provide 3 types of different morphologies, the first one has an orthorhombic crystalline phase and consists of branched micro and nanobelts, the other two morphologies are followed by stacked micro octahedron and agglomerate of octahedrons and sphere microstructures, both morphologies have orthorhombic crystalline phase. The palladium nanoparticles functionalization and superficial decoration process proved to be effective, but led to a great morphology change of the Sb2O3 samples. The as-grown Sb2O4 are mainly composed by micro- and nanowires mixed with branched micro-belts structures, both morphologies have orthorhombic crystalline phase
In this work, Sb2O3 and Sb2O4 micro- and nanostructures were synthesized by a vapor phase deposition method. Aiming to provide data on the structure of these samples, Xray diffraction, scanning electron microscopy and Raman spectroscopy techniques were used. The data analysis allowed to correctly identify the characteristics of the samples as well as to define a good and reproductible growth process. The as-grown Sb2O3 was submitted to palladium nanoparticles functionalization and superficial decoration process. The functionalized nanostructures were duly characterized by the same techniques applied to the pure oxide samples, with the purpose of verifying the effectiveness of the surface decoration process as well as obtaining information on the structure. The Sb2O3 synthesis provide 3 types of different morphologies, the first one has an orthorhombic crystalline phase and consists of branched micro and nanobelts, the other two morphologies are followed by stacked micro octahedron and agglomerate of octahedrons and sphere microstructures, both morphologies have orthorhombic crystalline phase. The palladium nanoparticles functionalization and superficial decoration process proved to be effective, but led to a great morphology change of the Sb2O3 samples. The as-grown Sb2O4 are mainly composed by micro- and nanowires mixed with branched micro-belts structures, both morphologies have orthorhombic crystalline phase
Descrição
Palavras-chave
Crescimento VLS, Sb2O3, Sb2O4, Redução carbotérmica, Nanoestruturas, Semicondutores, Microscopia eletrônica de varredura, Espectroscopia Raman, VLS growth, Carbothermal Reduction