Optical photo of 2D material WS2/MoS2heterojunction memristor (top left) and multiple cycle electrical performance test (top right); The movement of sulfur ions in WS2/MoS2heterojunction memristor under applied voltage (figure below).
Memristor is regarded as one of the key devices to break through the traditional Von Neumann computer architecture due to its capability of simulating the function of neural synapses. And among various memristive materials, two-dimensional (2D) material is a promising candidate to build advanced memristors with extremely high integration density and low power consumption. However, memristors based on conventional 2D material usually suffer from poor endurance and retention due to their vulnerability to material degradation during the formation/fusing processes of conductive filament channels within the switching media of 2D materials. To solve this problem, the research group of Professor Wei Xiong firstly used the 2D material WS2/MoS2heterojunction structure (Metal-heterojunction-metal, MHM) to realize the preparation of a relatively stable memristor. Different from the conventional structure, the resistance variation of the heterojunction memristor is mainly caused by the band modulation by sulfur ions at the interface of the heterojunction under the action of applied voltage. A prototype MHM memristor based on WS2/MoS2 heterojunction is successfully developed with a large memristor switching window up to 104 and a clearly extended endurance over 120 switching cycles, showing the advantage of WS2/MoS2 heterojunction over the individual MoS2or WS2layers in memristive performance. It is expected that the 2D material heterojunction memristor based on the MHM structure can not only achieve high-density integration of devices but also can effectively improve the stability of 2D material memristors, which is promising for the future artificial intelligence and brain-like computing systems.
Relevant workwaspublished in Nanoscale, 2021, Advance Article (https://doi.org/10.1039/D1NR01683K), The first author is Dr. Wenguang Zhang and Postdoctoral Dr. Hui Gao, and Professor Wei Xiong is the corresponding author. This work was supported by the National Natural Science Foundation of China (61774067), the Fundamental Research Funds for the Central Universities (HUST:2018KFYXKJC027) and the China Postdoctoral Foundation (2017M622417).
