Epitaxial growth of a 100-square-centimetre single-crystal hexagonal boron nitride monolayer on copper
Epitaxial growth of a 100-square-centimetre single-crystal hexagonal boron nitride monolayer on copper
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铜上 100 平方厘米单晶六方氮化硼单层的外延生长
DOI：
10.1038/s41586-019-1226-z
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发表时间：
2019-06-06
期刊：
影响因子：
64.8
通讯作者：
Liu, Kaihui
中科院分区：
文献类型：
--
作者：
Wang, Li;Xu, Xiaozhi;Liu, Kaihui
二维(2D)材料的发展为它们在电子学、光电子学和光伏领域的应用开辟了可能性，因为它们可以提供比传统硅基器件更小、更快的器件和更多的功能(1)。为2D组件--即导体、半导体和绝缘体--生长大而高质量的单晶的能力对于2D设备的工业应用至关重要(2-4)。原子层状六方氮化硼(HBN)具有稳定性好、表面平整、带隙大等优点，被认为是最好的二维绝缘体(5-12)。然而，二维hBN单晶的尺寸通常被限制在不到一毫米(13-18)，主要是因为这种晶体的生长困难；其中包括过度成核，这阻碍了从单个核心到大的单晶的生长，以及hBN晶格的三重对称性，这导致大多数衬底上的反平行域和孪晶边界(19)。在本文中，我们报道了在低对称性的铜(110)附近表面外延生长100平方厘米的hBN单层。结构表征和理论计算表明，外延生长是通过Cu211>；阶跃边与hBN锯齿形边的耦合实现的，打破了反平行hBN磁畴的等价性，使单向磁畴排列达到99%以上。利用厘米到原子尺度的表征技术，明确地展示了hBN结构域的生长动力学、单向排列和无缝缝合。我们的发现有望促进2D器件的广泛应用，并导致广泛的非中心对称2D材料的外延生长，如各种过渡金属二卤化物(20-23)，以产生大的单晶。
The development of two-dimensional (2D) materials has opened up possibilities for their application in electronics, optoelectronics and photovoltaics, because they can provide devices with smaller size, higher speed and additional functionalities compared with conventional silicon-based devices(1). The ability to grow large, high-quality single crystals for 2D components-that is, conductors, semiconductors and insulators-is essential for the industrial application of 2D devices(2-4). Atom-layered hexagonal boron nitride (hBN), with its excellent stability, flat surface and large bandgap, has been reported to be the best 2D insulator(5-12). However, the size of 2D hBN single crystals is typically limited to less than one millimetre(13-18), mainly because of difficulties in the growth of such crystals; these include excessive nucleation, which precludes growth from a single nucleus to large single crystals, and the threefold symmetry of the hBN lattice, which leads to antiparallel domains and twin boundaries on most substrates(19). Here we report the epitaxial growth of a 100-square-centimetre single-crystal hBN monolayer on a low-symmetry Cu (110) vicinal surface, obtained by annealing an industrial copper foil. Structural characterizations and theoretical calculations indicate that epitaxial growth was achieved by the coupling of Cu < 211 > step edges with hBN zigzag edges, which breaks the equivalence of antiparallel hBN domains, enabling unidirectional domain alignment better than 99 per cent. The growth kinetics, unidirectional alignment and seamless stitching of the hBN domains are unambiguously demonstrated using centimetre-to atomic-scale characterization techniques. Our findings are expected to facilitate the wide application of 2D devices and lead to the epitaxial growth of broad non-centrosymmetric 2D materials, such as various transition-metal dichalcogenides(20-23), to produce large single crystals.