Resistive Switching and Current Conduction Mechanisms in Hexagonal Boron Nitride Threshold Memristors with Nickel Electrodes

• Published in: Advanced functional materials Vol. 34; no. 15
• Main Authors: Völkel, Lukas, Braun, Dennis, Belete, Melkamu, Kataria, Satender, Wahlbrink, Thorsten, Ran, Ke, Kistermann, Kevin, Mayer, Joachim, Menzel, Stephan, Daus, Alwin, Lemme, Max C.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.04.2024
• Subjects: 2D materials; Boron; Boron nitride; Electrical measurement; Electrodes; Electrons; Filaments; hexagonal boron nitride; Insulation; Low resistance; Memory devices; Memristors; Metal fibers; Microscopy; Multilayers; Nickel; Physical properties; Switching; Temperature dependence; threshold switching; Transmission electron microscopy; Two dimensional materials
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202300428

The 2D insulating material hexagonal boron nitride (h‐BN) has attracted much attention as the active medium in memristive devices due to its favorable physical properties, among others, a wide bandgap that enables a large switching window. Metal filament formation is frequently suggested for h‐BN devices as the resistive switching (RS) mechanism, usually supported by highly specialized methods like conductive atomic force microscopy (C‐AFM) or transmission electron microscopy (TEM). Here, the switching of multilayer hexagonal boron nitride (h‐BN) threshold memristors with two nickel (Ni) electrodes is investigated through their current conduction mechanisms. Both the high and the low resistance states are analyzed through temperature‐dependent current–voltage measurements. The formation and retraction of nickel filaments along boron defects in the h‐BN film as the resistive switching mechanism is proposed. The electrical data are corroborated with TEM analyses to establish temperature‐dependent current–voltage measurements as a valuable tool for the analysis of resistive switching phenomena in memristors made of 2D materials. The memristors exhibit a wide and tunable current operation range and low stand‐by currents, in line with the state of the art in h‐BN‐based threshold switches, a low cycle‐to‐cycle variability of 5%, and a large On/Off ratio of 107. The current conduction mechanisms of hexagonal boron nitride‐based threshold memristors with nickel electrodes in high and low resistance states are investigated by temperature‐dependent current‐voltage measurements . Transmission electron microscopy images (TEM) confirm that the method is a valuable addition to analyzing resistive switching mechanisms with specialized TEM and conductive atomic force microscopy.