  With the decrease of the dimensions of electronic devices, the role played by
electrical contacts is ever increasing, eventually coming to dominate the
overall device volume and total resistance. This is especially problematic for
monolayers of semiconducting transition metal dichalcogenides (TMDs), which are
promising candidates for atomically thin electronics. Ideal electrical contacts
to them would require the use of similarly thin electrode materials while
maintaining low contact resistances. Here we report a scalable method to
fabricate ohmic graphene edge contacts to two representative monolayer TMDs -
MoS2 and WS2. The graphene and TMD layer are laterally connected with
wafer-scale homogeneity, no observable overlap or gap, and a low average
contact resistance of 30 k$\Omega$ $\mu$m. The resulting graphene edge contacts
show linear current-voltage (IV) characteristics at room temperature, with
ohmic behavior maintained down to liquid helium temperatures.
