Field-Effect Transistors from Artificial Charged Domain Walls in Stacked Van der Waals Ferroelectric α-In₂Se₃.

Abstract

Ferroelectric charged domain walls (CDWs) offer emergent electronic states that can serve as functional elements in high-density nonvolatile memory and neuromorphic computing. Yet, poor conductivity, structural instability, and lack of deterministic control limit their practical use. Moreover, the CDWs are typically out-of-plane and buried interfaces, which prohibits electrical access and prevents gate control of their carrier density. This work demonstrates the fabrication of artificial in-plane CDWs by stacking oppositely polarized flakes of van der Waals (vdW) ferroelectric <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mi>α</mi> <annotation>$\alpha$</annotation></semantics> </math> -In₂Se₃. Edge contact is utilized to electrically access the CDWs and integrate them into CDW-based field-effect transistors (CDW-FETs). CDW-FETs exhibit room-temperature conductance up to four orders of magnitude higher than single domains, exceeding previously reported CDWs by 2-9 orders of magnitude. Electron microscopy imaging reveals atomic reconstruction and interfacial heterogeneity in CDWs. Temperature and gate-dependent electrical and magneto-transport measurements confirm that interfacial band bending governs transport. Two transport mechanisms are identified in these CDW-FETs: variable-range hopping and thermally activated traps, showing a transition temperature of 80 K. These results establish artificial CDWs as on-demand, designable conductive channels in vdW ferroelectrics, advancing the understanding of CDW conduction mechanisms and bridging the gap toward device integration.