Uncovering the Role of Crystal Phase in Determining Nonvolatile Flash Memory Device Performance Fabricated from MoTe2-Based 2D van der Waals Heterostructures

Although the crystal phase of two-dimensional (2D) transitionmetaldichalcogenides (TMDs) has been proven to play an essential role infabricating high-performance electronic devices in the past decade,its effect on the performance of 2D material-based flash memory devicesstill remains unclear. Here, we report the exploration of the effectof MoTe2 in different phases as the charge-trapping layeron the performance of 2D van der Waals (vdW) heterostructure-basedflash memory devices, where a metallic 1T & PRIME;-MoTe2 or semiconducting 2H-MoTe2 nanoflake is used as the floatinggate. By conducting comprehensive measurements on the two kinds ofvdW heterostructure-based devices, the memory device based on MoS2/h-BN/1T & PRIME;-MoTe2 presents much better performance,including a larger memory window, faster switching speed (100 ns),and higher extinction ratio (10(7)), than that of the devicebased on the MoS2/h-BN/2H-MoTe2 heterostructure.Moreover, the device based on the MoS2/h-BN/1T & PRIME;-MoTe2 heterostructure also shows a long cycle (>1200 cycles)andretention (>3000 s) stability. Our study clearly demonstrates thatthe crystal phase of 2D TMDs has a significant impact on the performanceof nonvolatile flash memory devices based on 2D vdW heterostructures,which paves the way for the fabrication of future high-performancememory devices based on 2D materials.