| Autor: |
Lahwal, Ali, Bhattacharya, S., Jian He, Di Wu, Peterson, A., Poon, S. J., Williams, L., Dehkordi, A. Mehdizadeh, Tritt, T. M. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 2015, Vol. 117 Issue 14, p145101-1-145101-7, 7p, 1 Diagram, 1 Chart, 5 Graphs |
| Abstrakt: |
Nanocomposites have become a new paradigm for thermoelectric research in recent years and have resulted in the reduction of thermal conductivity via the nano-inclusion and grain boundary scattering. In this work, we report the preparation and thermoelectric study of SiGe-yttria stabilized zirconia (YSZ) nanocomposites prepared by Spark Plasma Sintering (SPS). We experimentally investigated the reduction of lattice thermal conductivity (κL) in the temperature range (30-800 K) of n-type Si80Ge20P2 alloys with the incorporation of YSZ nanoparticles (20-40 nm diameter) into the Si-Ge matrix. These samples synthesized by using the SPS technique were found to have densities>95% of the theoretical density. The thermal conductivity, at both low and high temperatures, was measured by steady state and laser flash techniques, respectively. At room temperature, we observed approximately a 50% reduction in the lattice thermal conductivity as result of adding 10% YSZ by volume to the Si80Ge20P2 host matrix. A phenomenological model developed by Callaway was used to corroborate both the temperature dependence and reduction of κL over the measured temperature range (30-800 K) of both Si80Ge20P2 and Si80Ge20P2+YSZ samples. The observed κL is discussed and interpreted in terms of various phonon scattering mechanisms such as alloy disorder, the Umklapp phonon scattering, and boundary scattering. In addition, a contribution from the phonon scattering by YSZ nanoparticles was further included to account for the κL of Si80Ge20P2+YSZ sample. The theoretical calculations are in reasonably good agreement with the experimental results for both the Si80Ge20P2 and Si80Ge20P2+YSZ alloys. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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