Intrinsic Dipole Coupling in 2D van der Waals Ferroelectrics for Gate-Controlled Switchable Rectifier

Miniaturization of device elements, such as ferroelectric diodes, depends on the downscaling of ferroelectric film, which is also crucial for developing high-density information storage technologies of ferroelectric random access memories (FeRAMs). Recently emerged ferroelectric two-dimensional (2D) van der Waals (vdWs) layered materials bring an additional opportunity to further increase the density of FeRAMs. A lateral, switchable rectifier is designed and fabricated based on atomically thin 2D α-In₂Se₃ ferroelectric diodes, thus breaking the thickness limitation of conventional ferroelectric films and achieving an unprecedented level of miniaturization. This is realized through the interrelated coupling between out-of-plane and in-plane dipoles at room temperature; that is, horizontal polarization reversal can be effectively controlled through a vertical electric field. Being further explored as a switchable rectifier, the obtained maximum value of rectification ratio for the α-In₂Se₃ based ferroelectric diode can reach up to 2.5 × 10³. These results indicate that 2D ferroelectric semiconductors can offer a pathway to develop next-generation multifunctional electronics.