Rotationally Commensurate Growth of MoS2 on Epitaxial Graphene

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• 作者：Xiaolong Liu ; Itamar Balla ; Hadallia Bergeron ; Gavin P. Campbell ; Michael J. Bedzyk ; Mark C. Hersam
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：January 26, 2016
• 年：2016
• 卷：10
• 期：1
• 页码：1067-1075
• 全文大小：562K
• ISSN：1936-086X

文摘

Atomically thin MoS₂/graphene heterostructures are promising candidates for nanoelectronic and optoelectronic technologies. Among different graphene substrates, epitaxial graphene (EG) on SiC provides several potential advantages for such heterostructures, including high electronic quality, tunable substrate coupling, wafer-scale processability, and crystalline ordering that can template commensurate growth. Exploiting these attributes, we demonstrate here the thickness-controlled van der Waals epitaxial growth of MoS₂ on EG via chemical vapor deposition, giving rise to transfer-free synthesis of a two-dimensional heterostructure with registry between its constituent materials. The rotational commensurability observed between the MoS₂ and EG is driven by the energetically favorable alignment of their respective lattices and results in nearly strain-free MoS₂, as evidenced by synchrotron X-ray scattering and atomic-resolution scanning tunneling microscopy (STM). The electronic nature of the MoS₂/EG heterostructure is elucidated with STM and scanning tunneling spectroscopy, which reveals bias-dependent apparent thickness, band bending, and a reduced band gap of ～0.4 eV at the monolayer MoS₂ edges.