Ferroelectric control of band structures in the two-dimensional Janus WSSe/In2Se3 van der Waals heterostructures

The reversible polarization of ferroelectric semiconductor In2Se3 can be used to realize the tunable photoelectric properties of the heterostructures. In this work, we construct the two-dimensional (2D) Janus WSSe/In2Se3 van der Waals heterostructures (vdWHs), where Janus WSSe monolayer has an intrinsic out-of-plane dipole moment. First-principles calculations show that when the Se-side of WSSe layer contacts with In2Se3, the reverse of In2Se3 polarization can induce the bandgap of the heterostructure switch between 0.95eV and 0.14 eV. However, when the S-side of WSSe layer is located at the interface, the vdWHs keep the type-II band alignment. In addition, changing the interlayer distance induces the transition from type-I to type-II band alignment, and the band gap values are also modified. The theoretical studies show that the 2D ferroelectric WSSe/In2Se3 vdWHs has possible applications in nano-optoelectronic devices.