Role of geometry and surface roughness in reducing phonon mean free path and lattice thermal conductivity of modulated nanowires
Role of geometry and surface roughness in reducing phonon mean free path and lattice thermal conductivity of modulated nanowires
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DOI：
10.1016/j.ijheatmasstransfer.2020.119818
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发表时间：
2020-08-01
影响因子：
5.2
通讯作者：
Hori, Takuma
中科院分区：
文献类型：
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作者：
Hori, Takuma
声子输运模拟进行了调查的几何形状和表面粗糙度的调制纳米线的热导率的影响。利用有限体积法和光线追迹法计算了纳米线的声子平均自由程，结果表明，在一定的表面积体积比下，通过制作复杂的结构可以减小纳米线的平均自由程。然后，调制的纳米线的表面的镜面反射率的一部分进行了调整。模拟结果表明，镜面反射度对平均自由程的影响取决于镜面反射度调整表面的位置;特别是平均自由程对颈部表面的镜面反射度敏感，而对其他部位的镜面反射度不敏感。最后，通过使用模拟的平均自由程和其他声子输运性质从第一性原理计算得到的热导率进行了评估。有人发现，优化的几何形状和表面粗糙度可以减少足够大的热导率，这种效果是有益的，在一些半导体器件。(C)2020爱思唯尔有限公司版权所有。
Phonon transport simulations were performed to investigate the effects of geometry and surface roughness on the thermal conductivity of modulated nanowires. The finite volume method and ray tracing method were utilized to determine the phonon mean free path. The simulation results showed that the mean free path of the nanowire can be reduced by fabricating intricate structures under a constant ratio of surface area to volume. Then the specularity of the parts of the surfaces of the modulated nanowires was tuned. The simulations revealed that the impact of the specularity on the mean free path depends on the location of the surface whose specularity was tuned; in particular, the mean free path was sensitive to the specularity of the surfaces of neck parts but insensitive to that of other parts. Finally, the thermal conductivity was evaluated by using the simulated mean free path and other phonon transport properties obtained from first-principle calculations. It was found that optimization of the geometry and surface roughness can reduce sufficiently large thermal conductivities; this effect is beneficial in some semiconductor devices. (C) 2020 Elsevier Ltd. All rights reserved.