Enhanced tunnel electroresistance in BAs/In2S3 ferroelectric tunnel junction through ferroelectric control of band alignments

Abstract

We have designed two-dimensional ferroelectric tunnel junctions (FTJs) utilizing BAs/In${}_2$S${}_3$ van der Waals heterostructures and explored their transport characteristics. At low bias voltage, a pronounced difference in current magnitudes under different polarization states is observed, leading to a giant tunneling electroresistance (TER) ratio of $10^8\text{\%}$. Analysis of the projected band structures reveals changes in band alignment from type-III to type-I under the ferroelectric polarization reversal. Further discussions indicate that polarization reversal can cause a variation in the total charge transfer, consequently altering the Fermi level’s position in the BAs and In${}_2$S${}_3$ layers. This alteration results in a transition between metallic and semiconducting states, thus achieving a high TER ratio. These findings imply great potential of high-performance 2D FTJs, which may contribute to the development of non-volatile storage devices and ferroelectric field-effect transistors.