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

Abstract

Metal oxide devices that exhibit resistive swi tching 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 sys tems that two-state resistive behavior arises from the formation and rupture of conductive fil aments spanning the oxide layer. However, means for controlling the filament geometr y, which critically influences conduction, have largely been unexamined. Here, we explore the connection between filament geometry and con- ductance in a model resistive switching system b ased on the junction of two nickel/nickel oxide core/shell nanowires. Variable temperature curr ent-voltage measurements indicate that either wide metallic filaments or narrow semiconducti ng filaments can be preferentially formed by varying the current compliance during electrofo rmation. Metallic filaments behave as a conven- tional metallic resistance in series with a small barrier, while semiconduc ting filaments behave as quantum point contacts. The ability to tune filament geometry and behavior through the electroforming process may open avenues for en hanced functionality in nanoscale me mristive systems