Giant Isotope Effect of Thermal Conductivity in Silicon Nanowires
Giant Isotope Effect of Thermal Conductivity in Silicon Nanowires
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DOI：
10.1103/physrevlett.128.085901
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发表时间：
2022-02-23
影响因子：
8.6
通讯作者：
Wu, Junqiao
中科院分区：
文献类型：
--
作者：
Ci, Penghong;Sun, Muhua;Wu, Junqiao
同位素纯化的半导体可能比它们的天然同位素混合对应物更好地散热，因为它们具有更高的导热率（kappa）。但是在室温下对于Si的益处是低的，总计对于本体Si-28的卡伯值比对于本体天然Si（Si-nat）的卡伯值仅高10%。我们发现，在这种散装行为形成鲜明对比，Si-28（99.92%富集）纳米线具有高达150%的高卡伯比Si-nat纳米线具有相似的直径和表面形态。使用第一性原理声子色散模型，这种巨大的同位素效应是由于相互增强的同位素散射和表面散射的声子在硅纳米线，通过传输声子的原生无定形二氧化硅壳相关。这封信发现了迄今为止报道的所有材料中在室温下最强的kappa同位素效应，并激发了同位素富集半导体在微电子学中的潜在应用。
Isotopically purified semiconductors potentially dissipate heat better than their natural, isotopically mixed counterparts as they have higher thermal conductivity (kappa). But the benefit is low for Si at room temperature, amounting to only similar to 10% higher kappa for bulk Si-28 than for bulk natural Si (Si-nat). We show that in stark contrast to this bulk behavior, Si-28 (99.92% enriched) nanowires have up to 150% higher kappa than Si-nat nanowires with similar diameters and surface morphology. Using a first-principles phonon dispersion model, this giant isotope effect is attributed to a mutual enhancement of isotope scattering and surface scattering of phonons in Si-nat nanowires, correlated via transmission of phonons to the native amorphous SiO2 shell. The Letter discovers the strongest isotope effect of kappa at room temperature among all materials reported to date and inspires potential applications of isotopically enriched semiconductors in microelectronics.