Figure 16.

Schematic representation of the evolution of metal bridges (conducting filaments) in Cu/PPX/ITO memristive devices and the consequent quantum conductance effect. (a): Fragment of the pristine sandwich structure, having some surface irregularities on the top electrode. The orange pellets represent Cu atoms. (b): A positive voltage is applied to the top electrode of the structure; copper ions begin to move to the cathode (ITO) under the action of an electric field. (c): Copper ions reach the bottom electrode and reduce, so a conductive filament begins to grow. (d): The conductive filament is completely formed; quantized conductance is not observed. (e): A negative voltage is applied to the top electrode; copper ions begin to move backward to it. A quasi-point contact is formed, so the conductance is quantized, becoming approximately equal to G₀. (f): The conductive filament has ruptured; conductance is much less than G₀ [154]. Reprinted from Organic Electronics, Vol. 74, A.A. Minnekhanov, B.S. Shvetsov, M.M. Martyshov, K.E. Nikiruy, E.V. Kukueva, M.Y. Presnyakov, P.A. Forsh, V.V. Rylkov,, V.V. Erokhin, V.A. Demin, and A.V. Emelyanov, “On the resistive switching mechanism of parylene-based memristive devices”, pages 89–95, Copyright (2019), with permission from Elsevier.