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CdO como el óxido conductor transparente arquetípico. Sistemática de los efectos del radio iónico y la estructura
Yu Yang1, Shu Jin, Julia E Medvedeva
1Department of Chemistry, Materials Research Center, Northwestern University, Evanston, Illinois 60208-3113, USA.
Journal of the American Chemical Society
|June 16, 2005
Resumen
Las películas delgadas de óxido de cadmio (CYO) dopadas con ítrio muestran una excelente transparencia óptica y conductividad. El dopaje Y mejora la brecha de banda óptica, con propiedades óptimas alcanzadas en el dopaje del 1,2-1,3% para aplicaciones en óxidos conductores transparentes.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física del estado sólido Física del estado sólido
- Tecnología de película delgada.
Sus antecedentes:
- Los óxidos conductores transparentes (TCO) son cruciales para los dispositivos optoelectrónicos.
- El óxido de cadmio (CdO) es un material TCO prometedor, pero sus propiedades pueden ajustarse mediante dopaje.
- El dopaje de yttrio (Y) ofrece una vía para modificar las características eléctricas y ópticas de CdO.
Objetivo del estudio:
- Para sintetizar y caracterizar películas delgadas de CdO (CYO) dopadas con yttrium.
- Investigar la influencia del dopaje Y en las propiedades estructurales, eléctricas y ópticas del CdO.
- Para comparar los efectos del dopaje Y con otros dopajes (In, Sc) utilizando métodos experimentales y teóricos.
Principales métodos:
- La deposición de vapor químico metálico orgánico (MOCVD) para el crecimiento de la película delgada.
- Difracción de rayos X (XRD) para el análisis de la estructura de fase y la microestructura.
- Mediciones de la transmitancia óptica y de la conductividad eléctrica.
- Cálculos de la estructura de la banda electrónica.
Principales resultados:
- Se cultivaron con éxito películas delgadas CYO policristalinas puras de fase en sustratos de vidrio y MgO{100}.
- Las películas exhibieron >80% de transmitancia óptica en el rango visible.
- El dopaje de Y amplió la brecha de banda a 3.27 eV (cambio de Burstein-Moss).
- El dopaje óptimo de Y (1.2-1.3%) produjo conductividades de 8.540 S/cm (vidrio) y 17.800 S/cm (MgO100)).
- El radio iónico y la estructura electrónica del dopante influyen significativamente en los parámetros de la red, la movilidad de la portadora y la eficiencia del dopaje.
Conclusiones:
- El dopaje de ittrio es eficaz para mejorar el rendimiento de los óxidos conductores transparentes basados en CdO.
- El estudio proporciona información sobre las relaciones estructura-propiedad de los sistemas CdO dopados.
- Los hallazgos experimentales y teóricos destacan la importancia de la elección del dopante para optimizar las características de TCO.
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