Indexed by: Journal paper

First Author: yangzhe

Correspondence Author: TONG HAO

Co-author: 缪向水,TONG HAO,徐明,He Qiang,龚传涛,蔡经纬,张大友

Journal: Applied Physics Letters

Affiliation of Author(s): 华中科技大学

Discipline: Engineering

First-Level Discipline: Electronic Science And Technology

Document Type: J

Volume: 121

Issue: 20

Page Number: 203508

Key Words: Phase transitions, Electrical properties and parameters, Energy efficiency, Joule heating, Crystallography, Raman spectroscopy, Resistive switching, Transmission electron microscopy, Chemical processes, Phase change memories

DOI number: 10.1063/5.0127160

Date of Publication: 4487-12-01

Abstract: Phase change memory (PCM) is considered as a leading candidate for next generation data storage as well as emerging computing device, but the advancement has been hampered by high switching energy due to the melting process and amorphous relaxation induced large resistance drift. Polymorphic crystal-crystal transition without amorphization in metal dichalcogenides (TMDs) could be employed to solve these issues. Yet, the mechanism is still controversy. A melting-free PCM made of two dimensional (2D) MoTe2, which exhibits unipolar resistive switching (RS) and multi-level states with substantially reduced resistance drift via joule heating, is reported in this work. The device is first prepared based on the temperature dependence of Raman spectrum and electrical transport investigations on MoTe2 films. Significantly improved device performances on energy efficiency, switching speed, and memory window are further achieved by electrode size scaling down, indicating the key role of localized heating. Then, device scale transmission electron microscopy images reveal that the resistive switching stems from the transition between semiconducting 2H phase and metallic 1T0 phase. An entropy induced Te vacancies model is proposed to explain the reversible phase change mechanism in the MoTe2 based device. This study paves the way for further development of PCM based on atomically thin 2D TMDs, aiming for high density storage-class memory and high-precision neuromorphic computing.

Links to published journals: https://pubs.aip.org/aip/apl/article/121/20/203508/2834732