Nanostructured Graphene, DTU Nanotech, Technical University of Denmark,
Kgs. Lyngby 2800, Denmark
Two-dimensional (2D) semiconductors such as
transition metal dichalcogenides (TMDs) are attracting considerable interest as
novel materials for atomically thin and flexible field-effect transistor (FET)
devices. Recently, a promising FET setup has been proposed which employs graphene
as the electrode material to provide gate-tunable resistance at the contact,
and van der Waals assembly to protect the device from the environment by
encapsulation [1-3]. Using largescale quantum transport simulations, we have investigated
the role of the stacking order in a layered device formed by a MoS2
channel contacted by graphene electrodes, with the aim of providing guidelines
on how to shape the device in order to achieve maximum performance. We show
that the stacking order of the 2D layers dramatically impacts the distribution
of carriers at the interface between the graphene and the TMD in the gated
device, which ultimately determines its electronic transport characteristics.
Our results are relevant for the design of electrode-semiconductor interfaces
in FETs based entirely on two-dimensional materials.
1. X. Cui et al., Nature Nanotech., AOL, doi:10.1038/nnano.2015.70
2. Y. Liu et al., Nano Lett., 15, 3030 (2015)
3. Avsar A. et al. ACS Nano, 9, 4138 (2015)
Daniele Stradi is Hans Christian Ørsted
fellow in the Theoretical Nanoelectronics group (Prof. Mads Brandbyge) at the
Center for Nanostructured Graphene and at DTU Nanotech, Technical University of
Denmark. His current research interests focus on the investigation of graphene
as an electrode material using first-principles quantum transport simulations.
He received his B.Sc. degree in Chemistry from the University of Trieste (2009)
and his Ph.D. in Theoretical Chemistry from the Autonomous University of Madrid
(2013), with a thesis on the chargetransfer properties of organic monolayers
self-assembled on epitaxial graphene.