title: Large area molybdenum disulphide- epitaxial graphene vertical Van der Waals heterostructures.
abstract: Two-dimensional layered transition metal dichalcogenides (TMDCs) show great potential for optoelectronic devices due to their electronic and optical properties. A metal-semiconductor interface, as epitaxial graphene - molybdenum disulfide (MoS2), is of great interest from the standpoint of fundamental science, as it constitutes an outstanding platform to investigate the interlayer interaction in van der Waals heterostructures. Here, we study large area MoS2-graphene-heterostructures formed by direct transfer of chemical-vapor deposited MoS2 layer onto epitaxial graphene/SiC. We show that via a direct transfer, which minimizes interface contamination, we can obtain high quality and homogeneous van der Waals heterostructures. Angle-resolved photoemission spectroscopy (ARPES) measurements combined with Density Functional Theory (DFT) calculations show that the transition from indirect to direct bandgap in monolayer MoS2 is maintained in these heterostructures due to the weak van der Waals interaction with epitaxial graphene. A downshift of the Raman 2D band of the graphene, an up shift of the A1g peak of MoS2 and a significant photoluminescence quenching are observed for both monolayer and bilayer MoS2 as a result of charge transfer from MoS2 to epitaxial graphene under illumination. Our work provides a possible route to modify the thin film TDMCs photoluminescence properties via substrate engineering for future device design.
authors.affiliation: Laboratoire de Photonique et de Nanostructures (CNRS- LPN), Route de Nozay, 91460 Marcoussis, France.
authors.forename: Debora
authors.initials: D
authors.lastname: Pierucci
authors.affiliation: Laboratoire de Photonique et de Nanostructures (CNRS- LPN), Route de Nozay, 91460 Marcoussis, France.
authors.forename: Hugo
authors.initials: H
authors.lastname: Henck
authors.affiliation: Department of Physics and Astronomy, University of Pennsylvania, 209S 33rd Street, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Carl H
authors.initials: CH
authors.lastname: Naylor
authors.affiliation: Laboratoire de Photonique et de Nanostructures (CNRS- LPN), Route de Nozay, 91460 Marcoussis, France.
authors.forename: Haikel
authors.initials: H
authors.lastname: Sediri
authors.affiliation: Institut des Nanosciences de Paris, UPMC, 4 place Jussieu, boîte courrier 840, 75252 Paris cedex 05, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Lhuillier
authors.affiliation: Department of Physics and Astronomy, University of Pennsylvania, 209S 33rd Street, Philadelphia, Pennsylvania 19104, USA.|Laboratoire d'Innovation en Chimie des Surfaces et Nanosciences, DSM/NIMBE/LICSEN (CNRS UMR 3685), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
authors.forename: Adrian
authors.initials: A
authors.lastname: Balan
authors.affiliation: Synchrotron-SOLEIL, Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
authors.forename: Julien E
authors.initials: JE
authors.lastname: Rault
authors.affiliation: SPEC, CEA, CNRS, Universite Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
authors.forename: Yannick J
authors.initials: YJ
authors.lastname: Dappe
authors.affiliation: Synchrotron-SOLEIL, Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
authors.forename: François
authors.initials: F
authors.lastname: Bertran
authors.affiliation: Synchrotron-SOLEIL, Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
authors.forename: Patrick Le
authors.initials: PL
authors.lastname: Fèvre
authors.affiliation: Department of Physics and Astronomy, University of Pennsylvania, 209S 33rd Street, Philadelphia, Pennsylvania 19104, USA.
authors.forename: A T Charlie
authors.initials: ATC
authors.lastname: Johnson
authors.affiliation: Laboratoire de Photonique et de Nanostructures (CNRS- LPN), Route de Nozay, 91460 Marcoussis, France.
authors.forename: Abdelkarim
authors.initials: A
authors.lastname: Ouerghi