Monolayer atomic crystal molecular superlattices
Monolayer atomic crystal molecular superlattices
复制标题
单层原子晶体分子超晶格
DOI：
10.1038/nature25774
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发表时间：
2018-03-08
期刊：
影响因子：
64.8
通讯作者：
Duan, Xiangfeng
中科院分区：
文献类型：
--
作者：
Wang, Chen;He, Qiyuan;Duan, Xiangfeng
基于石墨烯或二硫化钼等二维原子晶体的货车范德华异质结构的人工超晶格，提供了现有材料无法企及的技术机会。制造这种人造超晶格的典型策略依赖于艰苦的逐层剥离和重新堆叠，产量和再现性有限。自下而上的化学气相沉积方法可以产生高质量的异质结构，但对于高阶超晶格来说变得越来越困难。用碱金属离子嵌入选定的二维原子晶体提供了一种替代超晶格结构的方法，但这些结构通常稳定性差，电子性质严重改变。在这里，我们报告了一种电化学分子嵌入方法，一类新的稳定的超晶格中，单层原子晶体交替与分子层。使用黑磷作为模型系统，我们表明，插层与十六烷基三甲基溴化铵产生单层磷烯分子超晶格中的层间距离是在黑磷的两倍以上，有效地隔离磷烯单层。电输运的研究表明，从单层磷分子超晶格制造的晶体管的开/关电流比超过107，沿着具有良好的流动性和上级稳定性。我们进一步表明，几种不同的二维原子晶体，如二硫化钼和二硒化钨，可以插入不同大小和对称性的季铵分子，以产生一个广泛的类定制的分子结构，层间距离，相组成，电子和光学性能的超晶格。这些研究为基础研究和潜在的技术应用定义了一个通用的材料平台。
Artificial superlattices, based on van der Waals heterostructures of two-dimensional atomic crystals such as graphene or molybdenum disulfide, offer technological opportunities beyond the reach of existing materials,,. Typical strategies for creating such artificial superlattices rely on arduous layer-by-layer exfoliation and restacking, with limited yield and reproducibility,,,,. The bottom-up approach of using chemical-vapour deposition produces high-quality heterostructures,,but becomes increasingly difficult for high-order superlattices. The intercalation of selected two-dimensional atomic crystals with alkali metal ions offers an alternative way to superlattice structures,,, but these usually have poor stability and seriously altered electronic properties. Here we report an electrochemical molecular intercalation approach to a new class of stable superlattices in which monolayer atomic crystals alternate with molecular layers. Using black phosphorus as a model system, we show that intercalation with cetyl-trimethylammonium bromide produces monolayer phosphorene molecular superlattices in which the interlayer distance is more than double that in black phosphorus, effectively isolating the phosphorene monolayers. Electrical transport studies of transistors fabricated from the monolayer phosphorene molecular superlattice show an on/off current ratio exceeding 107, along with excellent mobility and superior stability. We further show that several different two-dimensional atomic crystals, such as molybdenum disulfide and tungsten diselenide, can be intercalated with quaternary ammonium molecules of varying sizes and symmetries to produce a broad class of superlattices with tailored molecular structures, interlayer distances, phase compositions, electronic and optical properties. These studies define a versatile material platform for fundamental studies and potential technological applications.