Figure 2
Electrical characterization of nanopaper memory. All of the measurements were performed in atmospheric air conditions at room temperature. (a) Current–voltage (I–V) curves of nanopaper memory devices. The device initially showed an insulative pristine state (purple). After the first soft breakdown process called the forming process, the device showed reversible resistance switching between the low-resistance state (LRS; red) and the high-resistance state (HRS; blue). (b) Retention characteristics for both the LRS and HRS of the nanopaper memory. The readout voltage was 0.1 V. No significant degradation of the resistance state was observed for at least 104 s, with the resistance ratio maintained at >107, indicating the nonvolatility of the nanopaper memory device. (c) Multilevel memory effect of the nanopaper memory device. The compliance current was varied (50 μA, 500 μA and 1 mA) to create different LRSs. The readout voltage was 0.1 V. Distinct LRSs were observed according to the range of the compliance current. (d) Retention characteristics of resistance states for multilevel operation. The readout voltage was 0.1 V.
