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Grandes mejoras de la potencia térmica y la movilidad de la portadora en semiconductores a granel diseñados por
Yuanfeng Liu1, Pranati Sahoo, Julien P A Makongo
1Department of Materials Science and Engineering, University of Michigan, Ann Arbor, 48109, USA.
Journal of the American Chemical Society
|April 24, 2013
Resumen
Los investigadores mejoraron los materiales termoeléctricos incrustando puntos cuánticos de Heusler completos en una matriz de medio Heusler. Esta estrategia aumenta significativamente la potencia térmica y la movilidad del portador, allanando el camino para dispositivos termoeléctricos avanzados.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física de la materia condensada Física de la materia condensada
- Nanotecnología La nanotecnología es la nanotecnología.
Sus antecedentes:
- Los semiconductores convencionales se enfrentan a limitaciones para mejorar simultáneamente la potencia térmica (S) y la conductividad eléctrica (σ) debido al acoplamiento adverso a través de la densidad de la portadora (n).
- El dopaje y la química de sustitución ofrecen un éxito limitado en la superación de estas propiedades de transporte acopladas.
Objetivo del estudio:
- Demostrar la eficacia de los puntos cuánticos de Heusler (FH) integrados de manera coherente en la adaptación de las propiedades del portador de carga.
- Para lograr mejoras simultáneas en el poder térmico y la movilidad del portador en nanocompuestos basados en NiSn de tipo n Ti ((0.1) Zr ((0.9).
Principales métodos:
- Incorporación de puntos cuánticos FH (QD) dentro de una matriz Ti{0.1) Zr{0.9) NiSn de media Heusler.
- Investigando la influencia de los QD de FH en la densidad del portador, la movilidad y la masa efectiva.
- Analizando el papel de las barreras potenciales formadas en la interfaz QD-matriz.
Principales resultados:
- Simultáneamente se lograron grandes mejoras en el poder térmico (hasta 200%) y la movilidad del portador (hasta 43%) en los nanocompuestos Ti{0.1) Zr{0.9) Ni{1+x) Sn.
- Los FH QD crearon barreras potenciales, reduciendo la densidad efectiva del portador y aumentando la masa efectiva, lo que mejoró el termopoder.
- La mejora del tiempo de relajación del portador contribuyó al sorprendente aumento de la movilidad.
Conclusiones:
- La incorporación coherente de FH QDs es una estrategia prometedora para manipular el transporte de la carga portadora en semiconductores a granel.
- Este enfoque permite mejoras significativas en las propiedades termoeléctricas, lo que potencialmente conduce a materiales termoeléctricos de alta figura de mérito.
- La estrategia basada en QD ofrece una nueva vía para el diseño de materiales termoeléctricos de próxima generación.
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