Correlation between crystallinity and resistive switching behavior of sputtered WO3 thin films

• Correlation between crystallinity and switching behavior of sputtered WO3 thin films.
• The annealing-caused crystallinity change affects the switching behaviors.
• The Ag conducting formation is influenced by the crystalline structure.
• The as-deposited WO3 films are low crystalline structure, large switching ratio and fluctuating I–V hysteresis.
• The annealed WO3 films are crystallized compact structure, small switching ratio and stability I–V hysteresis.

The as-deposited WO3 thin films were post-annealed at different temperatures (300 °C and 600 °C) in air to investigate a correlation between crystallinity and switching behavior of WO3 thin films. Associating the results of XRD, FTIR, XPS and FESEM measurements, the annealing-caused crystallinity change contributes to the variation of the switching behaviors of the WO3 thin films. The as-deposited WO3 films with low crystalline structure are preferred for random Ag conducting path, resulting in large switching ratio but fluctuating I–V hysteresis, whereas the annealed WO3 films with crystallized compact structure limits Ag conducting path, favoring the stable I–V hysteresis but small switching ratio. It is therefore concluded that electrochemical redox reaction-controlled resistance switching depends not only on electrode materials (inert and reactive electrodes) but also on crystallinity of host oxide.