Combining single
-
layer
two
-
dimensional semiconducting transition metal dichalcogenides (TMDs)
with graphene
layer in van der Waals heterostructures
offers an intriguing means of controlling the electronic properties through
these
heterostructures
. Her
e
, we report
the
electronic
and structural
properties of transferred single layer WS
2
on
epitaxial graphene using
micro
-
Raman spectroscopy,
a
ngle
-
resolv
ed photoemission spectroscopy measurements
(ARPES)
and Density Functional Theory
(DFT)
calculations
.
The results
show good electronic properties as well as
well
-
defined band arising from the
strong splitting of the single layer WS
2
valence band at K points
, with a
maximum splitting of 0.44 eV.
By comparing our
DFT
results with local and hybrid functionals, we find the
top
valence band of the
experimental
heterostructure
is close
to the calculations for
suspended
single layer
WS
2
.
.
Our
results provide an i
mportant reference for future studies of electronic properties of WS
2
and
its
applications in
valleytronic devices.