Forming-free resistive switching memories based on titanium-oxide nanoparticles fabricated at room temperature

In this work, we present symmetric metal-insulator-metal bipolar memristors based on room-temperature deposition of charged titanium-oxide nanoparticles formed in vacuum by a physical process. One of the most striking features of these devices is that they do not require a forming step, which is to be related to protrusions of the top electrode material inside the intrinsically porous nanoparticle films. Furthermore, we report that deposition under substrate biasing conditions strongly affects the structural and electrical properties of the produced titanium oxide nanoparticle films including their bipolar switching behaviour.