AVS 61st International Symposium & Exhibition
    2D Materials Focus Topic Monday Sessions
       Session 2D+AS+EM+NS+SS-MoA

Paper 2D+AS+EM+NS+SS-MoA6
Electronic Structure Modification in van der Waals Heterostructures: Interlayer Hybridization in the Case of Graphene/MoS2

Monday, November 10, 2014, 3:40 pm, Room 310

Session: Dopants, Defects, and Interfaces in 2D Materials 
Presenter: Matthias Batzill, University of South Florida
Authors: M. Batzill, University of South Florida
H. Coy-Diaz, University of South Florida
M.C. Asensio, Synchrotron Soleil, France
J. Avila, Synchrotron Soleil
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Artificial van der Waals heterostructures promise to combine materials with diverse properties. Simple mechanical stacking or conventional growth of molecular hetero-layers would enable fabrication of novel materials or device-structures with atomically precise interfaces. Because covalent bonding in these layered materials is limited to molecular-planes, interface interactions between dissimilar materials are expected to modify the properties of the individual layers only weakly. Here we prepare graphene/MoS2 heterostuctures by transferring CVD-grown graphene onto a MoS2 substrate. It is shown that high quality interfaces between graphene and MoS2 can be obtained by UHV annealing . The quality of the graphene is demonstrated by atomic resolution scanning tunneling microscopy of ultraflat graphene. The electronic structure of the interface between the polycrystalline graphene and a MoS2 substrate is measured by angle resolved photoemission spectroscopy (ARPES) and nano-ARPES utilizing a focused photon beam at the SOLEIL synchrotron. We show that at the Fermi-level graphene exhibits a perfect, gapless and undoped Dirac-cone. However, in regions where the π-band of graphene overlaps with states of the MoS2 substrate, opening of several band-gaps are observed. This demonstrates that the electronic properties in van der Waals heterostructures can be significantly modified by interlayer interaction and thus exemplifying opportunities for tuning materials properties of graphene and other 2D-materials by interfacing them with dissimilar van-der Waals materials.