Dynamic Processes of Resistive Switching in Metallic Filament-Based Organic Memory Devices

Dynamic formation/rupture processes of metallic filament have been clarified in solid electrolyte- and oxide-based resistive memory devices, whereas they remain exclusive in organic ones. Here we report these dynamic processes in Cu/poly (3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester/indium-tin oxide (ITO) structure, which exhibits a typical bipolar resistive switching effect. Under illumination, an open circuit voltage of -0.15 V exists in high-resistance state, yet it vanishes in low-resistance state owing to the emergence of Cu filament. By combining the symmetry of current-voltage curves with corresponding energy band diagrams in different resistance states, it is demonstrated that the Cu filament grows from Cu/organics interface, ends at organics/ITO interface, and ruptures near organics/ITO interface. This work might advance the insight into resistive switching mechanisms in organic-based resistive memories.