Interfacial Resistive Switching of Niobium-Titanium Anodic Memristors with Self-Rectifying Capabilities

• Published in: Nanomaterials (Basel, Switzerland) Vol. 14; no. 4; p. 381
• Main Authors: Knapic, Dominik, Minenkov, Alexey, Atanasova, Elena, Zrinski, Ivana, Hassel, Achim Walter, Mardare, Andrei Ionut
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 19-02-2024; MDPI
• Subjects: Alloy systems; anodic memristor; Base metal; Combinatorial analysis; Composition; Dielectric films; Electrodes; interfacial; Libraries; Materials; Memory devices; Memristors; Mixed oxides; Nb-Ti compositional library; neuromorphic computing; Niobium; self–rectifying; Structural analysis; Structure; Switching; Thin films; Titanium; Austria; Netherlands; Germany; Nb-Ti compositional library; anodic memristor; self–rectifying; interfacial; neuromorphic computing
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano14040381

A broad compositional range of Nb-Ti anodic memristors with volatile and self-rectifying behaviour was studied using a combinatorial screening approach. A Nb-Ti thin-film combinatorial library was co-deposited by sputtering, serving as the bottom electrode for the memristive devices. The library, with a compositional spread ranging between 22 and 64 at.% Ti was anodically oxidised, the mixed oxide being the active layer in MIM-type structures completed by Pt discreet top electrode patterning. By studying
sweeps, memristors with self-rectifying and volatile behaviour were identified. Moreover, all the analysed memristors demonstrated multilevel properties. The best-performing memristors showed HRS/LRS (high resistive state/low resistive state) ratios between 4 and 6 × 10
and very good retention up to 10
successive readings. The anodic memristors grown along the compositional spread showed very good endurance up to 10
switching cycles, excluding those grown from alloys containing between 31 and 39 at.% Ti, which withstood only 10 switching cycles. Taking into consideration all the parameters studied, the Nb-46 at.% Ti composition was screened as the parent metal alloy composition, leading to the best-performing anodic memristor in this alloy system. The results obtained suggest that memristive behaviour is based on an interfacial non-filamentary type of resistive switching, which is consistent with the performed cross-sectional TEM structural and chemical characterisation.