Transparent-conductive-oxide (TCO) buffer layer effect on the resistive switching process in metal/TiO₂/TCO/metal assemblies

Abstract

The effect of a transparent conductive oxide (TCO) buffer layer on the insulator matrix and on the resistive switching process in the metal/TiO 2 /TCO/metal assembly was studied depending on the material of the TCO (ITO-(In 2 O 3 ) 0.9 (SnO 2 ) 0.1 or SnO 2 or ZnO). For the first time electro-physical studies and near edge x-ray absorption fine structure (NEXAFS) studies were carried out jointly and at the same point of the sample, providing direct experimental evidence that the switching process strongly influences the lowest unoccupied bands and the local atomic structure of the TiO 2 layers. It was established that a TCO layer in a metal/TiO 2 /TCO/metal assembly is an additional source of oxygen vacancies for the TiO 2 film. The R L (R H ) states are achieved presumably with the formation (rupture) of the electrically conductive path of oxygen vacancies. Inserting an Al 2 O 3 thin layer between the TiO 2 and TCO layers to some extent restricts the processes of migration of the oxygen ions and vacancies, and does not allow the anti-clockwise bipolar resistive switching in a Au/ TiO 2 /Al 2 O 3 /ITO/Au assembly. The greatest value of the ratio R H /R L is observed for the assembly with a SnO 2 buffer layer that will provide the maximum set of Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.intermediate states (recording analog data) and increase the density of information recording in this case.

NEXAFS study of electronic and atomic structure of active layer in Al/indium tin oxide/TiO2 stack during resistive switching

“…Note that earlier [33] the possibility of switching in the air in all the studied samples was confirmed by implementing the resistive switching in a specially designed box under a nitrogen atmosphere. The resistive switching processes were shown to be almost identical in ambient and nitrogen atmosphere.…”

“…Earlier [33] we revealed that metal/TCO/TiO 2 (TCO is a transparent conducting oxide) assemblies demonstrate the memristor effect after synthesis (without additional annealing) that provides progress towards understanding the nature of the memristor effect. Also it was established that after the switching process these structures can be retained for a long time.…”

Millivolt Modulation of Plasmonic Metasurface Optical Response via Ionic Conductance

“…In case of the Ag/Al 2 O 3 /ITO heterostructures studied here, both migration Ag ions and oxygen vacancies are likely contributors to transport and device operation. Indeed, it has been previously demonstrated that ITO layers incorporated in a memristive device can absorb or provide oxygen vacancies under an applied bias . Furthermore, one may imagine that the change in ionic concentration at the ITO/Al 2 O 3 interface may be dictating the observed optical modulation.…”

Effect of interfacial oxide thickness on the photocatalytic activity of magnetron‐sputtered TiO2 coatings on aluminum substrate

“…The increase in the conductivity can be seen in the ZRA where the current is high without UV‐light. Moreover, the OCP measurement for TiO 2 on Ti show the voltage drop in the dark, which is closer to the base level compared to other samples, indicating much less charge accumlation .…”

“…Moreover, the Al 2 O 3 can reduce and limit vacancies formed in the TiO 2 coating due to a conductive substrate . The Al 2 O 3 layer is known to be an insulator with a wide bandgap . The bandgap of amorphous anodic Al 2 O 3 layer is found to be 5.1–7.3 eV .…”