Quantum point contacts and resistive switching in Ni/NiO nanowire junctions

Abstract

Metal oxide devices that exhibit resistive switching are leading candidates for non-volatile memory applications due to their potential for fast switching, low-power operation, and high device density. It is widely accepted in many systems that two-state resistive behavior arises from the formation and rupture of conductive filaments spanning the oxide layer. However, means for controlling the filament geometry, which critically influences conduction, have largely been unexamined. Here, we explore the connection between filament geometry and conductance in a model resistive switching system based on the junction of two nickel/nickel oxide core/shell nanowires. Variable temperature current-voltage measurements indicate that either wide metallic filaments or narrow semiconducting filaments can be preferentially formed by varying the current compliance during electroformation. Metallic filaments behave as a conventional metallic resistance in series with a small barrier, while semiconducting filaments behave as quantum point contacts. The ability to tune filament geometry and behavior through the electroforming process may open avenues for enhanced functionality in nanoscale memristive systems.

Silicon Oxide (SiOx): A Promising Material for Resistance Switching?

“…Gao et al considered quantization in Ag/SiO 2 /In occurring at integer and half integer values of G 0 . Results pointing out in the same direction were also presented by a number of authors indicating that the idea of quantum conduction is more than a reasonable hypothesis. More conventional mechanisms such as Poole–Frenkel conduction and Schottky emission are also frequently invoked to model the high resistance state of SiO x films.…”

Recent Developments and Perspectives for Memristive Devices Based on Metal Oxide Nanowires

“…These devices exhibited unipolar resistive switching that was ascribed to a thermochemical reduction/oxidation that gives rise to the formation/rupture of a conductive filament at the cross‐point junction. A more detailed analysis of Ni/NiO cross‐point junctions was later reported by Oliver et al that pointed out that the filament geometry in the cross‐point can be tuned by varying the electroforming process, allowing the creation of wide metallic or narrow semiconducting filaments as revealed by I – V – T measurements. The switching mechanism in Ni/NiO cross‐point junctions was further elucidated by real time TEM investigation of filament creation/rupture by Ting et al that directly observed morphological changes at the cross‐junction point as a consequence of the oxygen ions migration that is responsible for the evolution of the conductive filament.…”

Co-percolation to tune conductive behaviour in dynamical metallic nanowire networks

“…Devices which displayed memristive loops also had small nonlinearities around low voltages, in line with recent reports and suggesting the filaments formed in the nanowire junctions are truly metallic. [40] These nonlinearities are expected given that most of the junctions will be Ni/Ni, with relatively few Ni/Ag junctions containing both an oxide and a polymer capacitive layer, and Please do not adjust margins Please do not adjust margins very few Ag/Ag junctions. Further addition of Ag nanowires will eventually lead to a network which is effectively no longer a heterogeneous Ni/Ag hybrid but a very sparse self-selected Ag nanowire network.…”