Caracterização de Zn0,96Mn0,04O por espectroscopia de absorção de raios X
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Data
2021-02-24
Autores
Oliveira, Breno Marcel Gomes de
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Universidade Estadual Paulista (Unesp)
Resumo
Os materiais semicondutores magnéticos diluídos (SMD) são alvos de extensivos estudos, tanto pelas suas propriedades como pelas aplicações tecnológicas em dispositivos eletrônicos, que cada vez mais demandam uma alta capacidade de processamento atrelada a dispositivos cada vez menores. Estes materiais possuem propriedades semicondutoras e magnéticas, devido a dopagem com íons que possuem momento magnético não nulo. Nesta monografia foram caracterizados semicondutores magnéticos diluídos de óxido de zinco, dopados com manganês, sintetizados através do método convencional de reação de estado solido. Além disso as amostras foram tratadas termicamente em forno elétrico convencional, nas temperaturas de 900 ºC, 1000 ºC, 1100 ºC e 1200 ºC numa atmosfera controlada de argônio e hidrogênio, que tem como intuito gerar defeitos no material. Amostras desse material foram caracterizadas com a técnica de espectroscopia de absorção de raios X. Essa técnica permitiu a caracterização da estrutura local ao redor dos átomos de Zn e Mn, sendo possível a determinação de distancias interatômicas e números de coordenação, podendo avaliar o efeito da dopagem. Foi possível determinar que átomos de Mn incorporados no material possuem estado de oxidação 2+ e contém vacâncias de oxigênio, o que era esperado dada a maneira em que foi sintetizado.
The diluted magnetic semiconductors (DMS) are objective of extensive scientific studies, both for their properties and for their technological applications in electronic devices, which have an increasing demand for high processing capacity coupled with progressively smaller devices. These materials have semiconducting and magnetic properties due to the doping of semiconductor matrices with ions that possess a nonnull magnetic moment. In this study we characterized manganese-doped zinc oxide diluted magnetic semiconductors, synthesized through the conventional method of solid-state reaction. The samples were heat-treated on a regular electric oven, at temperatures of 900 ºC, 1000 ºC, 1100 ºC and 1200 ºC in a controlled atmosphere of argon and hydrogen, which has the purpose of inducing structural defects into the material. This technique allowed the characterization of the local structure around the atoms of Zn and Mn, with the measurements of their interatomic distances and coordination numbers. It was possible to determine that the Mn atoms incorporated in the material have a 2+ oxidation state and contain oxygen vacancies, what was expected given the way the material was synthesized.
The diluted magnetic semiconductors (DMS) are objective of extensive scientific studies, both for their properties and for their technological applications in electronic devices, which have an increasing demand for high processing capacity coupled with progressively smaller devices. These materials have semiconducting and magnetic properties due to the doping of semiconductor matrices with ions that possess a nonnull magnetic moment. In this study we characterized manganese-doped zinc oxide diluted magnetic semiconductors, synthesized through the conventional method of solid-state reaction. The samples were heat-treated on a regular electric oven, at temperatures of 900 ºC, 1000 ºC, 1100 ºC and 1200 ºC in a controlled atmosphere of argon and hydrogen, which has the purpose of inducing structural defects into the material. This technique allowed the characterization of the local structure around the atoms of Zn and Mn, with the measurements of their interatomic distances and coordination numbers. It was possible to determine that the Mn atoms incorporated in the material have a 2+ oxidation state and contain oxygen vacancies, what was expected given the way the material was synthesized.
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Espectroscopia de absorção de raios X, Materiais semicondutores magnéticos diluídos, Óxido de zinco, Ciência dos materiais, XANES, EXAFS, X-ray absorption spectroscopy, Diluted magnetic semiconductor materials, Zinc oxide