In Situ Current-Accelerated Phase Cycling with Metallic and Semiconducting Switching in Copper Nanobelts at Room Temperature

Here, a current-accelerated phase cycling by an in situ current-induced oxidation process was demonstrated to reversibly switch the local metallic Cu and semiconducting Cu2O phases of patterned polycrystalline copper nanobelts. Once the Cu nanobelts were applied by a direct-current bias of similar to 0.5 to 1 V in air with opposite polarities, the resistance between several hundred ohms and more than M Omega can be manipulated. In practice, the thickness of 60 nm with a moderate grain size inhibiting both electromigration and permanent oxidation is the optimized condition for reversible switching when the oxygen supply is sufficient. More than 40% of the copper localized beneath the positively biased electrode was oxidized assisted by the Joule heating, blocking the current flow. On the contrary, the reduction reaction of Cu2O was activated by the thermally assisted electromigration of Cu atoms penetrating the interlayer at the reverse bias. Finally, based on a high on/off ratio, the fast switching and the scalable production, reusable feasibility based on copper nanobelts such as the memristor array was demonstrated.

Automated summary

A reversible switching of local metallic Cu and semiconducting Cu2O phases in polycrystalline copper nanobelts was demonstrated through in situ current-induced oxidation. The manipulation of resistance in the nanobelts was achieved by applying a direct-current bias in air with opposite polarities, along with the assistance of Joule heating and electromigration. This study highlights the potential of using copper nanobelts for applications such as memristor arrays, thanks to their high on/off ratio, fast switching, and scalable production.