Reactive Spark Plasma Sintering and Thermoelectric Properties of Zintl Semiconducting Ca[sub.14]Si[sub.19] Compound

We present a new reactive spark plasma sintering (RSPS) technique for synthesizing the rhombohedral Ca[sub.14]Si[sub.19] phase. The RSPS approach reduces the synthesis time from several weeks to a few minutes. The RSPS was found to be sufficient for obtaining a high level of purity of the Ca[sub.14]...

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Bibliographic Details
Published in:Crystals (Basel) 2023-02, Vol.13 (2)
Main Authors: Ali, Doaa Omar A, Fabbiani, Marco, Coulomb, Loïc, Bosc, Simon, Villeroy, Benjamin, Estournès, Camille, Estournès, Claude, Koza, Michael Marek, Beaudhuin, Mickaël, Viennois, Romain
Format: Article
Language:English
Subjects:
Analysis
Semiconductors
Sintering
Thermoelectricity
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Summary:We present a new reactive spark plasma sintering (RSPS) technique for synthesizing the rhombohedral Ca[sub.14]Si[sub.19] phase. The RSPS approach reduces the synthesis time from several weeks to a few minutes. The RSPS was found to be sufficient for obtaining a high level of purity of the Ca[sub.14]Si[sub.19] under a pressure of 100 MPa for a dwell period of 5 min at a temperature of 900 [sup.∘]C. From electrical resistivity measurements, we were able to determine the energy band gap of Ca[sub.14]Si[sub.19] to E[sub.g]=0.145(15) eV. The Seebeck coefficient shows Ca[sub.14]Si[sub.19] as a p-type semiconductor at room temperature. It becomes n-type with increasing temperature pointing to significant bipolar and conduction band contributions due to the narrow bandgap of the compound.
ISSN:2073-4352
2073-4352
DOI:10.3390/cryst13020262