Outstanding Thermal Conductivity of Single Atomic Layer Isotope-Modified Boron Nitride
Outstanding Thermal Conductivity of Single Atomic Layer Isotope-Modified Boron Nitride
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DOI：
10.1103/physrevlett.125.085902
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发表时间：
2020-08-21
影响因子：
8.6
通讯作者：
Santos, Elton J. G.
中科院分区：
文献类型：
--
作者：
Cai, Qiran;Scullion, Declan;Santos, Elton J. G.
具有高导热系数（kappa）的材料对于解决高度集成和小型化的现代设备中的废热耗散的挑战是有价值的。在此，我们报道了原子级薄的同位素纯六方氮化硼（BN）的快速合成，其是所有半导体和电绝缘体中kappa值最高的材料之一。富含B-11的单原子层（IL）BN在室温下具有高达1009 W/mK的kappa。我们发现，同位素工程主要抑制BN中的面外光学（ZO）声子散射，从而减少ZO与横向声学（TA）和纵向声学声子之间的声光散射。另一方面，减少厚度到一个单一的原子层减少层间相互作用，因此umklapp散射的面外声学（ZA）的声子，虽然这种厚度引起的K增强是不是戏剧性的，在自然发生的BN。原子薄的单同位素BN具有许多独特的性质，在货车德瓦尔斯器件和未来柔性电子产品的热管理方面很有前途。原子级薄BN的同位素工程也可能在2D材料中开辟其他有吸引力的应用和机会。
Materials with high thermal conductivities (kappa) are valuable to solve the challenge of waste heat dissipation in highly integrated and miniaturized modern devices. Herein, we report the fast synthesis of atomically thin isotopically pure hexagonal boron nitride (BN) and its one of the highest kappa among all semiconductors and electric insulators. Single atomic layer (IL) BN enriched with B-11 has a kappa up to 1009 W/mK at room temperature. We find that the isotope engineering mainly suppresses the out-of-plane optical (ZO) phonon scatterings in BN, which subsequently reduces acoustic-optical scatterings between ZO and transverse acoustic (TA) and longitudinal acoustic phonons. On the other hand, reducing the thickness to a single atomic layer diminishes the interlayer interactions and hence umklapp scatterings of the out-of-plane acoustic (ZA) phonons, though this thickness-induced K enhancement is not as dramatic as that in naturally occurring BN. With many of its unique properties, atomically thin monoisotopic BN is promising on heat management in van der Waals devices and future flexible electronics. The isotope engineering of atomically thin BN may also open up other appealing applications and opportunities in 2D materials yet to be explored.