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Síntesis y caracterización de hierro silicio boro (Fe5Si2B) y boruro de hierro (Fe3B) nanocables
1Department of Materials Science and Engineering, and Materials Research Institute, Northwestern University, 2220 Campus Drive, Evanston, IL 60208-3108, USA.
Journal of the American Chemical Society
|September 28, 2006
Resumen
Los investigadores sintetizaron nanocables de boro de silicio de hierro monocristalino y boruro de hierro utilizando deposición de vapor químico. El control preciso de las proporciones y temperaturas de los precursores permitió el crecimiento a medida de estos nanomateriales avanzados sin catalizadores.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Nanotecnología La nanotecnología es la nanotecnología.
- Química del estado sólido.
Sus antecedentes:
- La síntesis de nanocables es crucial para las aplicaciones electrónicas y magnéticas avanzadas.
- Controlar la fase y la morfología de los nanocables a base de hierro es un desafío.
- Los métodos de síntesis sin catalizadores son deseables por su pureza y rentabilidad.
Objetivo del estudio:
- Para sintetizar nanocables de un solo cristal de hierro silicio boro (Fe(5) Si(2) B) y boruro de hierro (Fe(3) B).
- Para investigar los métodos de deposición de vapor químico (CVD) sin catalizador para la fabricación de nanocables.
- Comprender la influencia de las proporciones y temperaturas de los precursores en la fase y el crecimiento de los nanocables.
Principales métodos:
- Deposición Química en Vapor (CVD, por sus siglas en inglés) utilizando precursores de yodo de hierro (FeI(2) y triioduro de boro (BI(3).
- Síntesis realizada con dióxido de silicio en sustratos de silicio (SiO) o de silicio (Si).
- Control preciso de la temperatura del sublimador FeI(2) y de las relaciones de vapor del precursor.
Principales resultados:
- Se han sintetizado con éxito nanocables monocristalinos Fe ((5) Si ((2) B y Fe ((3) B con diámetros de 5-50 nm y longitudes de 1-20 μm.
- Se identificaron rangos de temperatura específicos para la formación de nanocables de Fe(5) Si(2) B (540-570 °C) y Fe(3) B (430-470 °C).
- Se demostró que las proporciones de vapor de precursores y la formación de partículas de sustrato (Fe(5) SiB(2) o FeSi) son críticas para el control de fase y la nucleación.
- Se observó la dirección de crecimiento preferida a lo largo de <110> para ambos tipos de nanocables.
Conclusiones:
- El CVD sin catalizador es un método eficaz para producir nanocables Fe-Si-B y Fe-B controlados por fase.
- La adaptación de las proporciones y temperaturas de los precursores permite la síntesis selectiva de los nanocables Fe(5) Si(2) B y Fe(3) B.
- La comprensión de los mecanismos de nucleación en partículas específicas de sustrato es clave para controlar el crecimiento de nanocables.
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