Liu Yu-Zhu, Dai Jian-Qing, Yuan Jin, Zhao Miao-Wei
Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, P. R. China.
Phys Chem Chem Phys. 2023 Dec 13;25(48):33130-33140. doi: 10.1039/d3cp04408d.
In recent years, α-InSe 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-InSe/MoS with different ferroelectric polarization and design a 2D graphene (Gr)/InSe/MoS/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 InSe. Furthermore, the ferroelectricity persists in Gr/InSe/MoS/Gr vdW FTJs, and the presence of dielectric layer MoS in the FTJs enables the effective modulation of the tunneling barrier by altering the ferroelectric polarization of α-InSe, which results in two distinct conducting states denoted as "ON" and "OFF" with a large tunneling electroresistance (TER) ratio exceeding 10%. 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.
近年来，α-InSe因其室温铁电性和原子厚度在非易失性随机存储器件的小型化方面备受关注。在这项工作中，我们构建了具有不同铁电极化的二维（2D）范德华（vdW）异质结构α-InSe/MoS，并设计了一种具有对称电极的二维石墨烯（Gr）/InSe/MoS/Gr铁电隧道结（FTJ）。我们的计算表明，随着InSe铁电极化的反转，异质结构的能带排列可以从I型转变为II型。此外，铁电性在Gr/InSe/MoS/Gr vdW FTJs中持续存在，并且FTJs中介质层MoS的存在能够通过改变α-InSe的铁电极化来有效调制隧道势垒，这导致了两种不同的导电状态，分别表示为“开”和“关”，其具有超过10%的大隧道电阻（TER）比。这些发现表明了铁电vdW异质结构在FTJs设计中的重要性，并为在高密度铁电存储器件中应用具有面外极化的二维铁电/半导体异质结构提出了一条有前景的途径。
