Nonvolatile memory effect of an Al/2-Amino-4,5-dicyanoimidazole/Al structure

We studied electrical properties of 2-Amino-4,5-dicyanoimidazole (AIDCN), which has a very large electric dipole moment, using a simple Al/AIDCN/Al structure. The measured current-voltage characteristics showed that the device is switched from low-conductivity state (off-state) to high-conductivity state (on-state) at threshold voltage of 2.3 V. On/off ratio of the current was 103 at the bias of 1V. The device remained the on-state for two weeks even when the bias voltage was turned off. Furthermore, the on-state could be switched back to the off-state by applying a negative bias voltage. The switching time for transitions was estimated to be below 40 ns by using the transient technique. These results demonstrate that a nonvolatile memory device can be realized by the simple MIM structure. We will also show the temperature dependence of the electrical conductivity, ultraviolet photoemission spectra (UPS) to discuss mechanisms of the switching phenomena.