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Forming‐Free, Nonvolatile, and Flexible Resistive Random‐Access Memory Using Bismuth Iodide/van der Waals Materials Heterostructures
Author(s) -
Li ChiaShuo,
Kuo ShengWen,
Wu YuTien,
Fu FangYu,
Ni IChih,
Chen MeiHsin,
Wu ChihI
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202001146
Subject(s) - materials science , resistive random access memory , optoelectronics , bismuth , heterojunction , bend radius , nanotechnology , van der waals force , composite material , electrode , bending , chemistry , organic chemistry , molecule , metallurgy
Resistive switching devices based on halide perovskites exhibit promising potential in flexible resistive random‐access memory (RRAM) owing to low fabrication cost and low processing temperature. However, the toxicity of these materials hinders their commercialization. Herein, bismuth iodide (BiI 3 ) is employed as an insulator in RRAM. A monolayer of graphene or hexagonal boron nitride (h‐BN) is employed as a buffer layer to achieve van der Waals epitaxy of BiI 3 and meanwhile to prevent the intrusion of copper atoms. Thus, the film quality of the BiI 3 layer is greatly improved. Resistive‐switching devices with the structure of copper foil/h‐BN/BiI 3 /Au exhibited forming‐free characteristics, high on/off ratio, excellent data‐retention capability, and high endurance to 2500 sweep cycles. The forming‐free behavior in the devices is studied using X‐ray and ultraviolet photoemission spectroscopies, where a self‐formed conductive filament composed of metallic bismuth is observed. The formation and rupture of the conductive filament in the BiI 3 layer, which serves as the in‐gap channel, causes the switchable resistance of the devices. In addition, the devices exhibit excellent tolerance to bending, thus demonstrating high stability to at least 5000 bending cycles at a bending radius of 8.75 mm. This study demonstrates the promising potential of BiI 3 ‐based flexible resistive‐switching memories.