自首次从石墨中剥离出石墨烯以来,只有原子级厚度的层状(或二维)材料因其丰富奇特的物性占据着当今凝聚态物理和材料科学的中心舞台。不断扩大的二维材料家族,包括石墨烯、硅烯、磷烯、硼烯、六方氮化硼、过渡金属二硫族化合物、甚至强拓扑绝缘体等,不仅每个成员有其鲜明的个性,如独特的物性与制备方法,而且整个大家族又有其共性,如单层材料与衬底之间、层与层之间几乎都是依赖弱的范德瓦尔斯力耦合在一起。对任一个二维家族成员的深层理解,都可能对真正走进这一大家族有普适性价值。文章首先介绍范德瓦尔斯层状材料非平衡外延生长中常常遇到的主要原子过程和相应的形貌演化;进一步讨论范德瓦尔斯相互作用在二维材料横向或垂直堆叠的异质结中的重要性。在原子尺度的生长机理之外,也围绕二维材料的物性优化与功能化简要介绍一些最新进展,具体例子覆盖光学、电学、自旋电子学、催化等领域。
Since the first isolation of graphene from graphite by mechanical exfoliation,atomically-thin or layered materials have been occupying the central stage of today's condensed matter physics and materials sciences because of their rich and exotic properties in two dimensions(2D).Many members of the ever-expanding 2D materials family,such as graphene,silicene,phosphorene,borophene,hexagonal boron nitride,transition metal dichalcogenides,and even the strong topological insulators,share the distinct commonality of possessing relatively weak van der Waals(vd W) interlayer coupling,whereas each member may invoke its own fabrication approaches,and is characterized by its unique properties.In this review,we first discuss the major atomistic processes and related morphological evolution in the nonequilibrium epitaxial growth of vd W layered materials.Representative systems covered include the vd W epitaxy of both monolayered 2D systems and their lateral or vertical heterostructures,emphasizing the vital importance of the vd W interactions in these systems.We also briefly highlight some of the recentadvances in the property optimization and functionalization of 2D materials,using examples from the fields of optics,electronics,spintronics,and catalysis.