  Graphene has been widely used to construct low-resistance van der Waals (vdW)
contacts to other two-dimensional (2D) materials. However, a rise of electron
temperature of the graphene under a current flow has not been seriously
considered in many applications. Owing to its small electronic heat capacity
and electron-phonon coupling, electron temperature of the graphene can be
increased easily by the application of current. The heat generated within the
graphene is transferred to the contacted 2D materials through the vdW interface
and potentially influences their properties. Here, we compare the
superconducting critical currents of an NbSe2 flake for two different methods
of current application: with a Au/Ti electrode fabricated by thermal
evaporation and with a graphene electrode contacted to the NbSe2 flake through
a vdW interface. The influence of the heat transfer from the graphene to NbSe2
is detected through the change of the superconductivity of NbSe2. We found that
the critical current of NbSe2 significantly reduces when the current is applied
with the graphene electrode compared to that from the conventional Au/Ti
electrode. Further, since the electron heating in graphene exhibits ambipolar
back-gate modulation, we demonstrate the electric field modulation of the
critical current in NbSe2 when the current is applied with graphene electrode.
These results are attributed to the significant heat transfer from the graphene
electrode to NbSe2 through vdW interface.
