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

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.