The tunneling electroresistance effect in a van der Waals ferroelectric tunnel junction based on a graphene/In2Se3/MoS2/graphene heterostructure

Abstract

In recent years, α-In₂Se₃ has attracted great attention in miniaturizing nonvolatile random memory devices because of its room temperature ferroelectricity and atomic thickness. In this work, we construct two-dimensional (2D) van der Waals (vdW) heterostructures α-In₂Se₃/MoS₂ with different ferroelectric polarization and design a 2D graphene (Gr)/In₂Se₃/MoS₂/Gr ferroelectric tunnel junction (FTJ) with the symmetric electrodes. Our calculations show that the band alignment of the heterostructures can be changed from type-I to type-II accompanied by the reversal of the ferroelectric polarization of In₂Se₃. Furthermore, the ferroelectricity persists in Gr/In₂Se₃/MoS₂/Gr vdW FTJs, and the presence of dielectric layer MoS₂ in the FTJs enables the effective modulation of the tunneling barrier by altering the ferroelectric polarization of α-In₂Se₃, which results in two distinct conducting states denoted as “ON” and “OFF” with a large tunneling electroresistance (TER) ratio exceeding 10⁵%. These findings suggest the importance of ferroelectric vdW heterostructures in the design of FTJs and propose a promising route for applying the 2D ferroelectric/semiconductor heterostructures with out-of-plane polarization in high-density ferroelectric memory devices.