State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China.
Department of Physics, East China Normal University, Shanghai 200241, China.
Nat Commun. 2015 Jan 21;6:6160. doi: 10.1038/ncomms7160.
Hexagonal boron nitride (h-BN) has attracted significant attention because of its superior properties as well as its potential as an ideal dielectric layer for graphene-based devices. The h-BN films obtained via chemical vapour deposition in earlier reports are always polycrystalline with small grains because of high nucleation density on substrates. Here we report the successful synthesis of large single-crystal h-BN grains on rational designed Cu-Ni alloy foils. It is found that the nucleation density can be greatly reduced to 60 per mm(2) by optimizing Ni ratio in substrates. The strategy enables the growth of single-crystal h-BN grains up to 7,500 μm(2), approximately two orders larger than that in previous reports. This work not only provides valuable information for understanding h-BN nucleation and growth mechanisms, but also gives an effective alternative to exfoliated h-BN as a high-quality dielectric layer for large-scale nanoelectronic applications.
六方氮化硼（h-BN）因其优异的性能以及作为基于石墨烯器件的理想介电层的潜力而受到广泛关注。早期报道的通过化学气相沉积法获得的 h-BN 薄膜通常是多晶的，因为在衬底上的成核密度较高，所以晶粒较小。在这里，我们报告了在合理设计的 Cu-Ni 合金箔上成功合成了大单晶 h-BN 颗粒。研究发现，通过优化衬底中的 Ni 比，可以将成核密度大大降低至 60 个/mm(2)。该策略使得单晶 h-BN 晶粒的生长达到 7500μm(2)，大约比以前的报道大两个数量级。这项工作不仅为理解 h-BN 的成核和生长机制提供了有价值的信息，而且为剥离 h-BN 作为大规模纳米电子应用的高质量介电层提供了一种有效的替代方法。
