Thermal conduction in Si and SiGe phononic crystals explained by phonon mean free path spectrum
Thermal conduction in Si and SiGe phononic crystals explained by phonon mean free path spectrum
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DOI：
10.1063/1.4966190
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发表时间：
2016-10
影响因子：
4
通讯作者：
M. Nomura;J. Nakagawa;K. Sawano;J. Maire;S. Volz
中科院分区：
文献类型：
--
作者：
M. Nomura;J. Nakagawa;K. Sawano;J. Maire;S. Volz
实验研究了室温下单晶硅、非晶SiGe和多晶SiGe纳米结构中的热声子输运。通过改变在膜中形成的声子晶体的圆孔之间的最短距离来比较这三种材料的热导率的特征长度依赖性。这些材料的依赖性明显不同，这些差异可以解释的热声子平均自由程谱的三种材料。当特征长度与热声子平均自由程谱密集的区域相当时，纳米结构化对热导率降低有较大的影响。结果表明，热声子平均自由程谱可以定性估计的热导率测量与特征长度扫描。
Thermal phonon transport in single-crystalline Si, amorphous SiGe, and poly-SiGe nanostructures was investigated experimentally at room temperature. The characteristic length dependence of thermal conductivity was compared across these three materials by changing the shortest distance between the circular holes of phononic crystals formed in the membranes. The dependences clearly differ for these materials, and these differences can be explained by the thermal phonon mean free path spectra of the three materials. Nanostructuring has a larger impact on thermal conductivity reduction when the characteristic length is comparable to that in the region where the thermal phonon mean free path spectrum is dense. The results suggest that thermal phonon mean free path spectra can be estimated qualitatively by thermal conductivity measurements with characteristic length sweeps.