Orthogonal Electric Control of the Out‐Of‐Plane Field‐Effect in 2D Ferroelectric α‐In 2 Se 3

Abstract Tuning the electric properties of crystalline solids is at the heart of material science and electronics. Generating the electric field‐effect via an external voltage is a clean, continuous, and systematic method. Here, utilizing the unique electric dipole locking in van der Waals (vdW) ferroelectric α‐In 2 Se 3 , a new approach is reported to establish the electric gating effect, where the electrostatic doping in the out‐of‐plane direction is induced and controlled by an in‐plane voltage. With the vertical vdW heterostructure of ultrathin α‐In 2 Se 3 and MoS 2 , an in‐plane voltage gated coplanar field‐effect transistor with distinguished and retentive on/off ratio is validated. The results demonstrate unprecedented electric control of ferroelectricity, which paves the way for integrating 2D ferroelectric into novel nanoelectronic devices with broad applications.