In this work, we present a study on the resistive memory properties of ITO/MEH-PPV/Al devices. The pristine diode-like device, highly resistive, needs an electroforming process to turn the device into a memory with resistive switching. During electroforming, I-V sweeps are described using Schottky Emission (SE) and Fowler-Nordheim (FN) models, resulting in an injection barrier around ~ 0.8 to 0.9 eV that may be associated with injection through polymer/Al interface. At high resistance sate (HRS), the linear coefficient of the \(\text{l}\text{o}\text{g}I \text{x} \text{l}\text{o}\text{g}V\) curve is \(n\cong 1\) at low voltages and present a transition to \(n\cong 2\) when the device is close to switching voltage. At low resistance state (LRS), we observe \(n\cong 1\) up to the negative differential resistance (NDR). In our devices, exploring the reverse bias NDR at different levels, it is possible to observe multilevel conducting states in direct bias sweeps (opposite polarizations), unlike unipolar memories, that show multilevel states when exploring NDR at different levels in the same polarization direction. I-V multilevel sweeps are in accordance with the Quantum Point Contact Model (QPC). The resulting fitting parameters show that the number of filaments increases from one (at HRS) to 70 as multilevel state approach LRS. Also, the tgap decreases from \((0.59\pm 0.02) \text{n}\text{m}\) to \((0.44\pm 0.01) \text{n}\text{m}\) . The conductance found in terms of \({G}_{0}\) ( \(=2{e}^{2}/h\) \(= 7.75\text{x}{10}^{-5} \text{S}\) ) was \(1{G}_{0}\) up to \(11.5 {G}_{0}\) , compatible with values found from QPC model on I-V multilevel. Our results are consistent with the soft breakdown of an Al2O3 oxide layer at the polymer/metal interface.
