Uncovering the Role of Crystal Phase in Determining Nonvolatile Flash Memory Device Performance Fabricated from MoTe<sub>2</sub>-Based 2D van der Waals Heterostructures
Yunpeng Xia, Jiajia Zha, Haoxin Huang, Huide Wang, Peng Yang, Long Zheng, Zhuomin Zhang, Zhengbao Yang, Ye Chen, Hau Ping Chan, Johnny C. Ho, Chaoliang Tan
Abstract
Although the crystal phase of two-dimensional (2D) transition metal dichalcogenides (TMDs) has been proven to play an essential role in fabricating high-performance electronic devices in the past decade, its effect on the performance of 2D material-based flash memory devices still remains unclear. Here, we report the exploration of the effect of MoTe 2 in different phases as the charge-trapping layer on the performance of 2D van der Waals (vdW) heterostructure-based flash memory devices, where a metallic 1T′-MoTe 2 or semiconducting 2H-MoTe 2 nanoflake is used as the floating gate. By conducting comprehensive measurements on the two kinds of vdW heterostructure-based devices, the memory device based on MoS 2 /h-BN/1T′-MoTe 2 presents much better performance, including a larger memory window, faster switching speed (100 ns), and higher extinction ratio (10 7 ), than that of the device based on the MoS 2 /h-BN/2H-MoTe 2 heterostructure. Moreover, the device based on the MoS 2 /h-BN/1T′-MoTe 2 heterostructure also shows a long cycle (>1200 cycles) and retention (>3000 s) stability. Our study clearly demonstrates that the crystal phase of 2D TMDs has a significant impact on the performance of nonvolatile flash memory devices based on 2D vdW heterostructures, which paves the way for the fabrication of future high-performance memory devices based on 2D materials.