Large Switchable Photoconduction within 2D Potential Well of a Layered Ferroelectric Heterostructure

Abstract

Abstract The coexistence of large conductivity and robust ferroelectricity is promising for high‐performance ferroelectric devices based on polarization‐controllable highly efficient carrier transport. Distinct from traditional perovskite ferroelectrics, Bi 2 WO 6 with a layered structure shows a great potential to preserve its ferroelectricity under substantial electron doping. Herein, by artificial design of photosensitive heterostructures with desired band alignment, three orders of magnitude enhancement of the short‐circuit photocurrent is achieved in Bi 2 WO 6 /SrTiO 3 at room temperature. The microscopic mechanism of this large photocurrent originates from separated transport of electrons and holes in [WO 4 ] −2 and [Bi 2 O 2 ] +2 layers respectively with a large in‐plane conductivity, which is understood by a combination of ab initio calculations and spectroscopic measurements. The layered electronic structure and appropriately designed band alignment in this layered ferroelectric heterostructure provide an opportunity to achieve high‐performance and nonvolatile switchable electronic devices.