Highly Nonlinear Memory Selectors with Ultrathin MoS<sub>2</sub>/WSe<sub>2</sub>/MoS<sub>2</sub> Heterojunction
Hongye Chen, Tianqing Wan, Yue Zhou, Jianmin Yan, Changsheng Chen, Zhihang Xu, Songge Zhang, Ye Zhu, H.Y. Yu, Yang Chai
Abstract
Abstract Resistive random access memory (RRAM) crossbar arrays require the highly nonlinear selector with high current density to address a specific memory cell and suppress leakage current through the unselected cell. 3D monolithic integration of RRAM array requires selector devices with a small footprint and low‐temperature processing for ultrahigh‐density data storage. Here, an ultrathin two‐terminal n‐p‐n selector with 2D transition metal dichalcogenides (TMDs) is designed by a low‐temperature transfer method. The van der Waals contact between transferred Au electrodes and TMDs reduces the Fermi level pinning and retains the intrinsic transport behavior of TMDs. The selector with a single type of TMD exhibits a trade‐off between current density and nonlinearity depending on the barrier height. By tuning the Schottky barrier height and controlling the thickness of p‐type WSe 2 in MoS 2 /WSe 2 /MoS 2 n‐p‐n selector for a punch‐through transport, the selector shows high nonlinearity (≈ 230) and high current density (2 × 10 3 A cm −2 ) simultaneously. The n‐p‐n selectors are further integrated with a bipolar hexagonal boron nitride memory and calculate the maximum crossbar size of the 2D material‐based one‐selector one‐resistor according to a 10% read margin, which offers the possible realization of future 3D monolithic integration.