|Título||Tailoring thermal conductivity by engineering compositional gradients in Si1−x Ge x superlattices|
|Tipo de publicación||Journal Article|
|Año de publicación||2015|
|Autores||Ferrando-Villalba, P, Lopeandía, AF, Alvarez, FX, Paul, B, de Tomás, C, Alonso, MI, Garriga, M, Goñi, AR, Santiso, J, Garcia, G, Rodriguez-Viejo, J|
|Keywords||composition gradients, heat transport, SiGe superlattices, Thermal conductivity|
The transport properties of artificially engineered superlattices (SLs) can be tailored by incorporating a high density of interfaces in them. Specifically, SiGe SLs with low thermal conductivity values have great potential for thermoelectric generation and nano-cooling of Si-based devices. Here, we present a novel approach for customizing thermal transport across nanostructures by fabricating Si/Si1−x Ge x SLs with well-defined compositional gradients across the SiGe layer from x = 0 to 0.60. We demonstrate that the spatial inhomogeneity of the structure has a remarkable effect on the heat-flow propagation, reducing the thermal conductivity to ∼2.2 W·m−1·K−1, which is significantly less than the values achieved previously with non-optimized long-period SLs. This approach offers further possibilities for future applications in thermoelectricity.