Half‐Heusler superlattices as model systems for nanostructured thermoelectrics
Half‐Heusler superlattices as model systems for nanostructured thermoelectrics
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DOI：
10.1002/pssa.201532445
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发表时间：
2016-03
期刊：
影响因子：
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通讯作者：
P. Komar;T. Jaeger;Christoph Euler;E. Chávez Angel;U. Kolb;Mathis M. Müller;B. Balke;M. Aguirre-M.-Aguir
中科院分区：
文献类型：
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作者：
P. Komar;T. Jaeger;Christoph Euler;E. Chávez Angel;U. Kolb;Mathis M. Müller;B. Balke;M. Aguirre-M.-Aguir
热电材料的效率与无因次性能曲线ZT=S2σκT直接相关，因此提高ZT的手段之一是降低导热系数。我们的研究重点是半赫斯勒超晶格（SLs）及其周期与导热系数之间的关系。在室温下，用3 ω法测量了直流溅射TiNiSn/HfNiSn SLs的交叉平面导热系数，发现在所有SL周期，特别是小于20 nm的周期，κ都明显降低。此外，与文献数据相比，TiNiSn和HfNiSn单膜的导热系数有所降低。此外，我们还发现界面质量对κ有影响，即具有粗糙界面的SLs的导热系数比具有锋利界面的样品低约20%。
The efficiency of thermoelectric materials is directly related to the dimensionless figure of merit ZT=S2σκT , therefore, one of the means to improve ZT is to reduce the thermal conductivity. Our research focuses on half‐Heusler superlattices (SLs) and the relationship between the SL period and the thermal conductivity. The cross‐plane thermal conductivity of DC‐sputtered TiNiSn/HfNiSn SLs was measured by the 3 ω method at room temperature and a clear reduction of κ was achieved for all SL periods, in particular for periods smaller than 20 nm. Moreover, the thermal conductivities of TiNiSn and HfNiSn single films display reduced values compared to the literature data for bulk materials. Furthermore, we also found that the quality of interfaces has an influence on κ , namely, SLs with rougher interfaces exhibit an about 20% lower thermal conductivity compared to samples with sharp interfaces.