Resistive switching behaviour in polyaniline-CNT ReRAM device

In the present study, a detailed analysis of resistive switching behaviour in polyaniline (PANI) and its nanocomposite with carbon nanotubes (CNT) has been done. Pristine PANI device exhibits digital resistive switching with a threshold voltage of 1.75 V. For a 0.5wt% CNT-PANI device, the switching voltage is decreased to 0.8 V, and the resistive switching behavior changes from digital to analog switching. This analog behaviour is confirmed with potentiation and depression measurements, which show no abrupt gap between the potentiation and depression curves. Further addition of CNT (1wt% CNT-PANI) deteriorates the switching behaviour in the resistive switching device. The nonvolatile memory behavior of Pristine PANI, 0.5wt% CNT-PANI, and 1 wt% CNT-PANI devices is confirmed by their consistent endurance over 100 switching cycles, and retention measurement shows a clearly separated resistance states maintained for 2 h. The conduction mechanism is explained by resistance–temperature measurements, which show the semiconducting behaviour in the high resistance state (HRS) of pristine PANI with activation energy as 58 meV; however, the low resistance state of pristine PANI, as well as the HRS and LRS of 0.5wt% CNT and 1wt% CNT-PANI, exhibit metallic characteristics. The temperature coefficient of resistance (α) rises from 5.1 × 10^–3 K⁻¹ for pristine PANI to 3.1 × 10^–2 K⁻¹ for a 1wt% CNT-PANI nanocomposite device. This increase in α suggests that conduction in pristine PANI in LRS is primarily controlled by Ag ion transport; however, in the CNT-PANI nanocomposite devices, both Ag ions and CNT conducting filaments contribute, creating a more effective conduction pathway.