title: Direct synthesis of van der Waals solids.
abstract: The stacking of two-dimensional layered materials, such as semiconducting transition metal dichalcogenides (TMDs), insulating hexagonal boron nitride (hBN), and semimetallic graphene, has been theorized to produce tunable electronic and optoelectronic properties. Here we demonstrate the direct growth of MoS2, WSe2, and hBN on epitaxial graphene to form large-area van der Waals heterostructures. We reveal that the properties of the underlying graphene dictate properties of the heterostructures, where strain, wrinkling, and defects on the surface of graphene act as nucleation centers for lateral growth of the overlayer. Additionally, we show that the direct synthesis of TMDs on epitaxial graphene exhibits atomically sharp interfaces. Finally, we demonstrate that direct growth of MoS2 on epitaxial graphene can lead to a 10(3) improvement in photoresponse compared to MoS2 alone.
authors.affiliation: Department of Materials Science and Engineering and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Yu-Chuan
authors.initials: YC
authors.lastname: Lin
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.forename: Nestor
authors.initials: N
authors.lastname: Perea-Lopez
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Zhong
authors.initials: Z
authors.lastname: Lin
authors.forename: Xin
authors.initials: X
authors.lastname: Peng
authors.forename: Chia Hui
authors.initials: CH
authors.lastname: Lee
authors.forename: Ce
authors.initials: C
authors.lastname: Sun
authors.forename: Lazaro
authors.initials: L
authors.lastname: Calderin
authors.forename: Paul N
authors.initials: PN
authors.lastname: Browning
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bresnehan
authors.forename: Moon J
authors.initials: MJ
authors.lastname: Kim
authors.forename: Theresa S
authors.initials: TS
authors.lastname: Mayer
authors.forename: Mauricio
authors.initials: M
authors.lastname: Terrones
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Robinson