Near-infrared Polarization Modulation of Photonic Devices by Ferroelectric Polarization

Abstract

Heterojunction engineering is currently used as an effective strategy to modulate and enrich the optoelectronic properties of target materials. However, the strict energy band alignment and high external field energy driving the working band limit its implementation to some extent. Here, we present a novel photovoltaic/ferroelectric heterojunction, InSiTe₃/α-In₂Se₃, in which ferroelectric polarization easily and efficiently regulates the built-in electric field in the interlayer. By reversing the ferroelectric polarization direction of In₂Se₃, we find that the electronic band structure of InSiTe₃ shows a difference between closed (0 eV) and open (0.67 eV), which results in a logical control from ″0″ to ″1″. Further, this change in the electronic bands leads to a significant increase in light absorption intensity as well as blue- and red-shifting of the light absorption peaks. This is ascribed to variations in the direction of ferroelectric polarization affecting the interlayer charge transfer, leading to differences in the contribution of the electronic orbitals near the Fermi energy level. In photonic device simulations, the optical polarization anisotropy of InSiTe₃/α-In₂Se₃-based photonic devices in the near-infrared (NIR) band can be modulated by switching the direction of ferroelectric polarization of In₂Se₃ through an electric field. These results suggest that ferroelectric and photovoltaic heterojunction engineering can serve as a conventional tool for fully electronically modulating the performance of optoelectronic devices.