Thermal Conductivity Reduction in a Silicon Thin Film with Nanocones
Thermal Conductivity Reduction in a Silicon Thin Film with Nanocones
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DOI：
10.1021/acsami.9b08797
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发表时间：
2019-09-18
影响因子：
9.5
通讯作者：
Nomura, Masahiro
中科院分区：
文献类型：
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作者：
Huang, Xin;Gluchko, Sergei;Nomura, Masahiro
现代热电器件倾向于使用廉价、环境友好和CMOS兼容的材料，如硅。为了提高硅的热电性能，研究人员试图使用各种纳米结构化方法来降低其热导率。然而，这些方法中的大多数具有有限的效率，因为它们是昂贵的并且对硅的内部结构造成损害。在这里，我们提出了一种具有成本效益的，大面积的，和无掩模的纳米加工方法，在硅表面上创建外部纳米锥，同时保留其内部。我们的实验表明，这些纳米锥降低了超过40%的薄硅膜的热导率。利用修正的Callaway-Holland模型，研究了在4-295 K温度范围内，不同声子散射过程对热导率的影响。我们的结论是，纳米锥产生额外的表面散射，这导致热导率降低。所提出的纳米锥及其简单的制备方法对于硅基平面热电器件具有很好的应用前景。
Modern thermoelectric devices incline toward inexpensive, environmentally friendly, and CMOS-compatible materials, such as silicon. To improve the thermoelectric performance of silicon, researchers try to decrease its thermal conductivity using various nanostructuring methods. However, most of these methods have limited efficiency because they are costly and damaging for the internal structure of silicon. Here, we propose a cost-effective, large-area, and maskless nanofabrication method that creates external nanocones on the silicon surface while preserving its interior. Our experiments show that these nanocones reduce the thermal conductivity of thin silicon membranes by more than 40%. Using a modified Callaway-Holland model, we study how the thermal conductivity is affected by various phonon scattering processes in the 4-295 K temperature range. We conclude that the nanocones generate additional surface scattering, which causes the thermal conductivity reduction. The proposed nanocones and their simple fabrication method are promising for the planar thermoelectric devices based on silicon.