Improved performance of flexible citrus resistive memory device through air plasma

Flexible natural material-based electronics have attracted considerable attention because it can be applied in wearable applications and bio smart electronics. Natural material citrus is used as the dielectric layer in this work to develop flexible resistive switching memory devices, with plasma ITO surface as the bottom electrode (BE) to investigate the effects of air plasma on device performances. The work function difference between the top electrodes (TE) and BE can be increased with plasma treatment. After optimization, the flexible citrus resistive memory device with a large work function difference between the TE and BE exhibits a good ON/OFF ratio of larger than 103, a low set voltage of around 0.76 V, uniform distribution of set voltages, small coefficients of variation of high resistance state, and low resistance state currents, and a long retention time of more than 104 s. The air plasma can also modify the ITO surface to make the surface more hydrophilic. Thus, the citrus film is easier to attach to ITO, which improves the bending performance of the device. The device under a bending radius of 4.9 mm showed no significant ON/OFF ratio changes when compared with that of the flat state. This information on the correlation between the plasma treatment time and the work function of the ITO electrode would be very useful in obtaining stable and uniform resistive switching properties in the flexible natural material-based resistive memory.