  Multilayers based on quantum materials (complex oxides, topological
insulators, transition-metal dichalcogenides, etc) have enabled the design of
devices that could revolutionize microelectronics and optoelectronics. However,
heterostructures incorporating quantum materials from different families remain
scarce, while they would immensely broaden the range of possible applications.
Here we demonstrate the large-scale integration of compounds from two
highly-multifunctional families: perovskite oxides and transition-metal
dichalcogenides (TMDs). We couple BiFeO$_3$, a room-temperature multiferroic
oxide, and WSe$_2$, a semiconducting two-dimensional material with potential
for photovoltaics and photonics. WSe$_2$ is grown by molecular beam epitaxy and
transferred on a centimeter-scale onto BiFeO$_3$ films. Using angle-resolved
photoemission spectroscopy, we visualize the electronic structure of 1 to 3
monolayers of WSe$_2$ and evidence a giant energy shift as large as 0.75 eV
induced by the ferroelectric polarization direction in the underlying
BiFeO$_3$. Such a strong shift opens new perspectives in the efficient
manipulation of TMDs properties by proximity effects.
