Significant Reduction of Thermal Conductivity in Si/Ge Core-Shell Nanowires
Significant Reduction of Thermal Conductivity in Si/Ge Core-Shell Nanowires
复制标题
Si/Ge核壳纳米线的热导率显着降低
DOI：
10.1021/nl103718a
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发表时间：
2011-02-01
期刊：
影响因子：
10.8
通讯作者：
Poulikakos, Dimos
中科院分区：
文献类型：
--
作者：
Hu, Ming;Giapis, Konstantinos P.;Poulikakos, Dimos
我们报告的锗（Ge）涂层上的硅（Si）纳米线的热输运性质的非平衡分子动力学模拟的效果。我们的研究结果表明，一个简单的沉积的Ge壳层的厚度只有1至2个晶胞的单晶Si纳米线可以导致显着的75%的热导率在室温下相比，未涂覆的Si纳米线下降。通过分析声子的振动密度态和各特定模式的参与率，我们证明了Si/Ge核壳纳米线热导率的降低是由于Si/Ge界面处的长波声子模式和高频非传播扩散模式的抑制和局域化。
We report on the effect of germanium (Ge) coatings on the thermal transport properties of silicon (Si) nanowires using nonequilibrium molecular dynamics simulations. Our results show that a simple deposition of a Ge shell of only 1 to 2 unit cells in thickness on a single crystalline Si nanowire can lead to a dramatic 75% decrease in thermal conductivity at room temperature compared to an uncoated Si nanowire. By analyzing the vibrational density states of phonons and the participation ratio of each specific mode, we demonstrate that the reduction in the thermal conductivity of Si/Ge core hell nanowire stems from the depression and localization of long-wavelength phonon modes at the Si/Ge interface and of high frequency nonpropagating diffusive modes.