Optimized Resistive Switching in TiO2 Nanotubes by Modulation of Oxygen Vacancy Through Chemical Reduction

Abstract

The resistive switching behavior of 1-D TiO 2 nanotube-based resistive random access memory (ReRAM) is discussed in this article. Highly oriented TiO 2 nanotubes were synthesized by anodic oxidation method on a Ti substrate, which was used as the bottom electrode. To modulate the oxygen vacancy (VO) in TiO 2 nanotubes, hydrazine hydrate reduction was employed in the temperature range 60 °C-100 °C. After charactering the morphological, elemental, and crystallographic properties, the level of reduction in different TiO 2 nanotubes array was estimated by Raman, photoluminescence, and X-ray photoelectron spectroscopies. Au/TiO 2 nanotubes/Ti devices were fabricated by using TiO 2 nanotubes with various levels of reductions where thin and porous Au top electrode was used to make the resistive switching faster. TiO 2 Nanotubes array, reduced at 80 °C showed promising resistive switching performance with SET/RESET voltages of 2 V/1.8 V, R OFF /R ON of 19 at a read voltage of 0.5 V (25 °C) and stable endurance behavior after the 100th cycle. Interestingly, reduction temperature at 60 °C and 100°C, offered degraded resistive switching within the same voltage range. All the devices showed electroforming free bipolar resistive switching. Efforts were devoted to establish the role of V O and its tuning to improve the resistive switching behavior in 1-D TiO 2 nanotubes. This article systematically showcases the efficacy of 1-D metal oxide for potential ReRAM application and establishes an easy but efficient approach to improve the resistive switching by modulating oxygen vacancy in it.