No 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.

We have studied the stability of the resistive switching process in the Al/(In2O3)0.9(SnO2)0.1/TiO2 assembly grown by atomic layer deposition. Besides electrical characterization the effect of electric field on the atomic electronic structure of the TiO2 layer was studied using near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The region of the current instability in the I-V characteristics was revealed. Presumably this current instability is supported by the amorphous structure of the TiO2 film but is initiated by the surface morphology of the Al substrate. A formation of the O2 molecules was established which occurs specifically in the region of the current instability that is a result of electrical Joule heating manifestation.