高均一性二维碲化钼忆阻器阵列及其神经形态计算应用

二维过渡金属硫化合物是构建纳米电子器件的理想材料, 基于该材料体系开发用于信息存储和神经形态计算的忆阻器, 受到了学术界的广泛关注。受制于低成品率和低均一性问题, 二维过渡金属硫化合物忆阻器阵列鲜见报道。本研究采用化学气相沉积得到厘米级二维碲化钼薄膜, 并通过湿法转移和剥离工艺制备得到碲化钼忆阻器件。该碲化钼器件表现出优异的保持性(保持时间>500 s)、快速的阻变(SET时间~60 ns, RESET时间~280 ns)和较好的循环寿命(阻变2000圈后仍可正常工作)。该器件具有高成品率(96%)、低阻变循环间差异性(SET过程为6.6%, RESET过程为5.2%)和低器件间差异性(SET过程为19.9%, RESET过程为15.6%)。本工作成功制备出基于MoTe₂的3×3忆阻器阵列。在此基础上, 将研制的MoTe₂器件用于手写体识别, 实现了91.3%的识别率。最后, 通过对MoTe₂器件高低阻态的电子输运机制进行拟合分析, 揭示了该器件阻变源于类金属导电细丝的通断过程。本项工作表明大尺寸二维过渡金属硫化合物在未来神经形态计算中具有巨大的应用潜力。

High-uniformity Memristor Arrays Based on Two-dimensional MoTe2 for Neuromorphic Computing

Two-dimensional transition metal dichalcogenides are appealing materials for the preparation of nanoelectronic devices, and the development of memristors for information storage and neuromorphic computing using such materials is of particular interest. However, memristor arrays based on two-dimensional transition metal dichalcogenides are rarely reported due to low yield and high device-to-device variability. Herein, the 2D MoTe₂ film was prepared by the chemical vapor deposition method. Then the memristive devices based on 2D MoTe₂ film were fabricated through the polymethyl methacrylate transfer method and the lift-off process. The as-prepared MoTe₂ devices perform stable bipolar resistive switching, including superior retention characteristics (>500 s), fast switching (~60 ns for SET and ~280 ns for RESET), and excellent endurance (>2000 cycles). More importantly, the MoTe₂ devices exhibit high yield (96%), low cycle-to-cycle variability (6.6% for SET and 5.2% for RESET), and low device-to-device variability (19.9% for SET and 15.6% for RESET). In addition, a 3×3 memristor array with 1R scheme is successfully demonstrated based on 2D MoTe₂ film. And, high recognition accuracy (91.3%) is realized by simulation in the artificial neural network with the MoTe₂ devices working as synapses. It is found that the formation/rupture of metallic filaments is the dominating switching mechanism based on the investigations of the electron transport characteristics of high and low resistance states in the present MoTe₂ devices. This work demonstrates that large-scale two-dimensional transition metal dichalcogenides film is of great potential for future applications in neuromorphic computing.