Microscopic origin of bipolar resistive switching of nanoscale titanium oxide thin films

TL;DR

This paper uncovers the microscopic mechanism behind bipolar resistive switching in nanoscale titanium oxide films, showing oxygen ion migration at interfaces as the key process.

Contribution

It provides direct microscopic evidence linking oxygen ion drift to resistive switching, combining TEM and XPS techniques for the first time.

Findings

Oxygen ions accumulate at the top interface during switching.

Oxygen ion drift causes the resistive state changes.

Oxidation-reduction reactions modulate the switching behavior.

Abstract

We report a direct observation of the microscopic origin of the bipolar resistive switching behavior in nanoscale titanium oxide films. Through a high-resolution transmission electron microscopy, an analytical TEM technique using energy-filtering transmission electron microscopy and an in situ x-ray photoelectron spectroscopy, we demonstrated that the oxygen ions piled up at top interface by an oxidation-reduction reaction between the titanium oxide layer and the top Al metal electrode. We also found that the drift of oxygen ions during the on/off switching induced the bipolar resistive switching in the titanium oxide thin films.