Does platinum play a role in the resistance switching of ZnO nanowire-based devices?

Platinum is a largely employed material as electrode in resistive switching devices. However, it is not known if it might play an active role in the switching of Pt/ZnO/Cu devices when ZnO nanowires are employed as active layer. Here, we study theoretically if platinum can lead to a variation of the total resistance in such devices by inspecting how platinum adatoms behave on a ZnO nanowire surface. We show that, even though Pt can travel on ZnO under the effect of an electric field and, in principle, it can form a conductive filament, the large energy required to extract Pt atoms from the contact makes, in practice, impossible for platinum to be involved in changing the device resistance state. Platinum is then better suited as counter-electrode in RRAM coupled with a more active metal like copper.