Influence of oxygen ion drift on a negative difference behavior in a reset process of bipolar resistive switching

• A bipolar resistive switching cell has been fabricated with TiO2 bi-layer structure.
• The TiO2 bi-layer structure consists with different oxygen contents.
• Non-lattice oxygen ions were observed by X-ray photoelectron spectroscopy (XPS).
• On/off ratio in BPS was controlled by the amount of oxygen ion in top TiOx layer.

We present the oxygen ion drift-based resistive switching features of TiOx/TiOy bi-layer homo-junctions. The TiOx layer in this bi-layer configuration was designed to have a stoichiometric chemical composition of TiO2, while the TiOy layer was designed to have a non-stoichiometric chemical composition. X-ray photoelectron spectroscopy measurements were carried out before and after electro-forming to determine the role of non-lattice oxygen content. Variation of the oxygen ion content in the TiO2 layers resulted in changes in the on/off ratio and increased the non-lattice oxygen content. A possible switching mechanism based on oxygen ion content is discussed.