Two-Dimensional Ferroelectric C 2 N/In 2 Se 3 Heterobilayer with Tunable Electronic Property and Photovoltaic Effect.

Two-dimensional ferroelectric monolayer materials with reversible spontaneous polarization provide more regulatory dimensions for their relevant van der Waals heterostructures. Using first-principles calculations, we construct the C 2 N/In 2 Se 3 bilayer heterostructure and study its physical properties as well as the effects of E -field and strain. The results indicate that the intrinsic polarization of the component In 2 Se 3 monoalyer can significantly adjust the electronic properties of the C 2 N/In 2 Se 3 heterobilayer. When the polarization of the In 2 Se 3 monolayer points to the interface (up-In 2 Se 3 ), the C 2 N/In 2 Se 3 bilayer behaves as the type-I indirect band gap heterostructure, while it transforms to the type-II direct band gap heterostructure after reversing the polarization of the In 2 Se 3 monolayer (dp-In 2 Se 3 ). Furthermore, the two C 2 N/In 2 Se 3 heterostructures both have enhanced optical absorption in the visible region than the isolated In 2 Se 3 and C 2 N monolayers. More importantly, the external electric field and strain can easily regulate the electronic properties of the C 2 N/In 2 Se 3 heterostructures. The power conversion efficiency (PCE) of the type-II C 2 N/dp-In 2 Se 3 heterostructure is 8.16%, and the electric field of 0.1 V/Å and the strain of -2% can transform the C 2 N/up-In 2 Se 3 heterostructure into type-II one, conducive to the high PCE up to 24.03 and 24%, respectively. Our proposed C 2 N/In 2 Se 3 heterostructure is promising in future luminescent and photovoltaic fields, and our findings also provide a strategy for functionalizing 2D monolayer materials by the intrinsic polarization property of ferroelectric materials.