Memristive Behavior in Thin Anodic Titania

Abstract

A common material in creating memristors is titanium dioxide (TiO 2 ), grown by atomic layer deposition, sputtering, or sol-gel process. In this letter, we study the memristive behavior in thin TiO 2 films fabricated by brief electrochemical anodization of titanium. The effects of different anodization times and annealing are explored. We discover that inherent oxygenvacancies at the bottom Ti/TiO 2 interface naturally lead to memristive switching in nonannealed films. Annealing induces extra oxygen vacancies near the top metal/oxide interface, which leads to symmetric and ohmic current-voltage characteristics with a collapse of memristive switching. No clear dependence on anodization time was observed for times between 1 s and 1 min.

Application-wise nanostructuring of anodic films on titanium: a review

“…Memristive behaviour of non-stoichiometric oxides TiO 2 films generally present an insulating behaviour, but the presence of oxygen vacancies at the metalÀoxide interface introduces a peculiar electrical response as circuital elements known as memristance [120]: in some anodic oxides with nanoscale thickness resistivity is a function of current previously travelled through the oxide in the past (from where the memristor term arises), thus showing a bias-dependent bipolar switching response to current. [121,122] This is made possible in TiO 2 by two factors: its defective nature, with oxide stoichiometry varying from TiO 2 to TiO 2Àx , and the possibility of limiting its thickness to few tens of nanometres, as memristance is inversely proportional to the square of the oxide thickness. [123] Memristive devices are opening the way to a new generation of transistor-like devices with easy scaling-down possibilities, as well as nonvolatile memories with fast access and improved data density, and finally to the introduction of synapses in artificial neural networks.…”

Preparation of Au/TiO2/Ti memristive elements via anodic oxidation

“…Because of its unique porous structure, anodic titania is widely used in photocatalysis and photochromic systems [18,19], biomedical applications [20], gas sensors [21,22] and pigment preparation [23]. At the same time, the study of memristive properties was performed only in the few articles [24][25][26]. However, anodic oxidation technique allows to form amorphous highly non-stoichiometric titania, which can be considered as a promising active layer for memristive elements.…”

Fabrication of ZrO2 layer through electrohydrodynamic atomization for the printed resistive switch (memristor)

“…So scalability of the memristor depends a lot on the nano-fabrication of the insulating region. Different nanofabrication technologies are available for the insulating region in the MIM sandwich like atomic layer deposition [8], sputtering [9], sol-gel method [10] and anodization [11]. Some fabrication technologies are matured and some are being researched nowadays.…”