Digital versus analog resistive switching depending on the thickness of nickel oxide nanoparticle assembly

Abstract

The thickness-dependent digital versus analog resistive switching of nickel oxide (NiOx) nanoparticle assemblies was investigated in a Ti/NiOx/Pt structure. The NiiO(x) nanoparticles were chemically synthesized with similar to 5 nm diameter. The Ti/NiiO(x)/Pt structure with assembly thickness of similar to 60 nm exhibited the digital-type bipolar resistive switching. However, the assembly with a thickness of similar to 90 nm presented analog resistive switching with gradually decreasing resistance when sweeping -V while increasing resistance after applying +V. Repeating -V pulses decreased the resistance sequentially, but the high resistance was restored sequentially by repeating +V pulses, which is analogous to the potentiation and depression of adaptive synaptic motion.