Band Alignment and Minigaps in Monolayer MoS2-Graphene van der Waals Heterostructures.
Two-dimensional layered MoS2 shows great potential for nanoelectronic and optoelectronic devices due to its high photosensitivity, which is the result of its indirect to direct band gap transition when the bulk dimension is reduced to a single monolayer. Here, we present an exhaustive study of the band alignment and relativistic properties of a van der Waals heterostructure formed between single layers of MoS2 and graphene. A sharp, high-quality MoS2-graphene interface was obtained and characterized by micro-Raman spectroscopy, high-resolution X-ray photoemission spectroscopy (HRXPS), and scanning high-resolution transmission electron microscopy (STEM/HRTEM). Moreover, direct band structure determination of the MoS2/graphene van der Waals heterostructure monolayer was carried out using angle-resolved photoemission spectroscopy (ARPES), shedding light on essential features such as doping, Fermi velocity, hybridization, and band-offset of the low energy electronic dynamics found at the interface. We show that, close to the Fermi level, graphene exhibits a robust, almost perfect, gapless, and n-doped Dirac cone and no significant charge transfer doping is detected from MoS2 to graphene. However, modification of the graphene band structure occurs at rather larger binding energies, as the opening of several miniband-gaps is observed. These miniband-gaps resulting from the overlay of MoS2 and the graphene layer lattice impose a superperiodic potential.
Centre de Nanosciences et de Nanotechnologies, CNRS Univ. Paris-Sud, Université Paris-Saclay , C2N - Marcoussis, 91460 Marcoussis, France.
Debora
D
Pierucci
Centre de Nanosciences et de Nanotechnologies, CNRS Univ. Paris-Sud, Université Paris-Saclay , C2N - Marcoussis, 91460 Marcoussis, France.
Hugo
H
Henck
Synchrotron-SOLEIL , Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
Jose
J
Avila
Department of Physics and Astronomy, University of Pennsylvania , 209S 33rd Street, Philadelphia, Pennsylvania 19104 6396, United States.|LICSEN, NIMBE, CEA, CNRS, Université Paris Saclay , CEA Saclay, 91191 Gif-sur-Yvette, France.
Adrian
A
Balan
Department of Physics and Astronomy, University of Pennsylvania , 209S 33rd Street, Philadelphia, Pennsylvania 19104 6396, United States.
Carl H
CH
Naylor
Centre de Nanosciences et de Nanotechnologies, CNRS Univ. Paris-Sud, Université Paris-Saclay , C2N - Marcoussis, 91460 Marcoussis, France.
Gilles
G
Patriarche
SPEC, CEA, CNRS, Université Paris Saclay , CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
Yannick J
YJ
Dappe
Synchrotron-SOLEIL , Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
Mathieu G
MG
Silly
Synchrotron-SOLEIL , Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
Fausto
F
Sirotti
Department of Physics and Astronomy, University of Pennsylvania , 209S 33rd Street, Philadelphia, Pennsylvania 19104 6396, United States.
A T Charlie
AT
Johnson
Synchrotron-SOLEIL , Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex, France.
Maria C
MC
Asensio
Centre de Nanosciences et de Nanotechnologies, CNRS Univ. Paris-Sud, Université Paris-Saclay , C2N - Marcoussis, 91460 Marcoussis, France.
Abdelkarim
A
Ouerghi
MoS2; band alignment; graphene; heterostructures; van der Waals materials