title: Reliable and Low-Power Multilevel Resistive Switching in TiO2Nanorod Arrays Structured with a TiOxSeed Layer.
abstract: The electrical performance of TiO2nanorod array (NRA)-based resistive switching memory devices is examined in this paper. The formation of a seed layer on the fluorine-doped tin oxide (FTO) glass substrate after treatment in TiCl4solution, before the growth of TiO2NRAs on the FTO substrate via a hydrothermal process, is shown to significantly improve the resistive switching performance of the resulting TiO2NRA-based device. As fabricated, the Al/TiO2NRA/TiOxlayer/FTO device displayed electroforming-free bipolar resistive switching behavior while maintaining a stable ON/OFF ratio for more than 500 direct sweeping cycles over a retention period of 3 × 104s. Meanwhile, the programming current as low as ∼10-8A and 10-10A for low resistance state and high resistance state respectively makes the fabricated devices suitable for low-power memristor applications. The TiOxprecursor seed layer not only promotes the uniform and preferred growth of TiO2nanorods on the FTO substrate but also functions as an additional source layer of trap centers due to its oxygen-deficient composition. Our data suggest that the primary conduction mechanism in these devices arises from trap-mediated space-charge-limited current (SCLC). Multilevel memory performance in this new device is achieved by varying the SET voltage. The origin of this effect is also discussed.
authors.affiliation: Centre for Advanced Materials Joining, ‡Waterloo Institute of Nanotechnology, §Department of Mechanics and Mechatronics Engineering, and ∥Department of Physics and Astronomy, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Ming
authors.identifier: http://orcid.org/0000-0003-2018-4807
authors.initials: M
authors.lastname: Xiao
authors.affiliation: Centre for Advanced Materials Joining, ‡Waterloo Institute of Nanotechnology, §Department of Mechanics and Mechatronics Engineering, and ∥Department of Physics and Astronomy, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Musselman
authors.affiliation: Centre for Advanced Materials Joining, ‡Waterloo Institute of Nanotechnology, §Department of Mechanics and Mechatronics Engineering, and ∥Department of Physics and Astronomy, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Walter W
authors.initials: WW
authors.lastname: Duley
authors.affiliation: Centre for Advanced Materials Joining, ‡Waterloo Institute of Nanotechnology, §Department of Mechanics and Mechatronics Engineering, and ∥Department of Physics and Astronomy, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Y Norman
authors.initials: YN
authors.lastname: Zhou
keywords: TiO2 nanorod array; low power; multilevel memory; resistive switching; seed layer; space-charge-limited current