Forming-free bipolar resistive switching and quantum conductance in NiO/FTO structures

Abstract

Forming-free bipolar resistive switching and quantum conductance effects are reported for Au/NiO/FTO structures. The devices show multistep conductance changes during the RESET process for temperatures in the range from 295 to 373 K. Statistical histograms based on 650 switching cycles indicate that the conductivity changes are well represented by integer or half integer multiples of the quantum conductance G 0. Temperature dependent I-V measurements below the switching voltages can be described using a Poole-Frenkel model. The mechanism of forming-free bipolar switching and the quantum conductance effect in the Au/NiO/FTO structure is interpreted by multiple quasi-filaments existing in as-grown NiO films and the numbers for the multiple conducting filaments decrease gradually in RESET processes when they rupture gradually.