X-ray spectroscopic study of SrTiOx films with different interlayers

Filatova, E. O.; Sokolov, Andréy; Egorova, Yu. V.; Konashuk, Aleksei S.; Vilkov, O. Yu.; Gorgoi, Mihaela; Павлычев, А. А.

doi:10.1063/1.4809978

Cited by 15 publications

(14 citation statements)

References 69 publications

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“…This effect is well known in case of Ti 2p-absorption spectra of TiO2 and more expressed in the shape of feature b connected with the double-degenerate eg component [23,[30][31][32][33][34][35].…”

Section: Titanium 2p X-ray Absorptionmentioning

confidence: 77%

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

et al. 2017

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We present a study of the electronic and atomic structure of two series of SrTi1-xFexO3-δ (STFO) powders with different Fe content produced by two different methods, spray pyrolysis or modified Pechini synthesis, by means of soft X-ray absorption spectroscopy. Partial substitution of Ti by Fe atoms in SrTiO3 were found to cause asymmetric distortion of TiO6 octahedrons which increases with increasing Fe content that may violate the cubic symmetry of STFO. The presence mainly of Fe 3+ states in octahedral environment at small concentration of Fe atoms along with essentially smaller content of Fe 4+ states in octahedral environment where the latter contribution increases with increasing Fe content was traced. It is found that the modified Pechini method allows to synthesize more stable structures but a tendency of the SrOx formation in the structure prepared by this technique was marked. The spray pyrolysis method gives the structure free of SrO precipitates but the presence of Fe 3+ states in tetrahedral environment with Fe content higher than 50% and even a certain amount of Fe 2+ ions in an octahedral environment at concentrations higher than 75% in the STFO prepared by this method was established. The O1s (K)-absorption spectra point to increase in oxygen vacancy concentration with increasing Fe content. The lowest degree of structure distortions with enough high oxygen vacancy concentration was traced in STFO (x= 0.25 to x = 0.35) produced by modified Pechini synthesis, which makes it mostly appropriate for technical applications, e.g., as gas sensors, oxygen separation membranes or as fuel cell material.

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Section: Titanium 2p X-ray Absorptionmentioning

confidence: 77%

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

et al. 2017

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“…Keeping in mind that the O K-absorption spectrum of TiO 2 originates mainly from O 1s-to-valence transitions, the covalent bonding of the Ti 3d with the O 2p states gives rise to the unoccupied valence t 2g and e g orbitals in the octahedral field. Then it is plausible to conclude that the features a and b in the measured O K-absorption spectrum of the TiN are related to the Ti 3d states mixed with O 2p states 50 . In its turn, the second wide band c-d can be attributed to the O2p states mixed with Ti 4sp bands 60 .…”

Section: Resultsmentioning

confidence: 98%

Re-distribution of oxygen at the interface between γ-Al2O3 and TiN

Filatova

Konashuk

Sakhonenkov

et al. 2017

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Interface of TiN electrode with γ-Al2O3 layers was studied using near edge X-ray absorption fine structure, conventional X-ray photoelectron spectroscopy and photoelectron spectroscopy with high energies. Despite the atomic-layer deposited Al2O3 being converted into thermodynamically-stable polycrystalline cubic γ-phase by high-temperature (1000 or 1100 °C) anneal, our results reveal formation of a thin TiNxOy (≈1-nm thick) interlayer at the interface between γ-Al2O3 film and TiN electrode due to oxygen scavenging from γ-Al2O3 film. Formation of the TiO2 was not observed at this interface. As environmental effect, a strong oxidation resulting in formation of a TiO2(1.4 nm)/TiNxOy(0.9 nm) overlayers on the top of the TiN electrode is traced. Development of O-deficiency of γ-Al2O3 is observed and related to the polarization anisotropy due to the preferential orientation of spin states involved in the X-ray absorption in the plane parallel to the surface. Investigation of the TiN electrode reveals the predominantly “stretched” octahedra in its structure with the preferential orientation relative the interface with γ-Al2O3. This anisotropy can be correlated with ≈200 meV electron barrier height increase at the O-deficient TiN/γ-Al2O3 interface as compared to the TiN/γ-Al2O3 barrier formed under abundant oxidant supply condition as revealed by internal photoemission of electrons from TiN into the oxide.

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“…It has been established in [24][25][26] that inserting a thin buffer layer between the substrate and dielectric film affects the self-organization and the properties of the active layer. Taking into account a high concentration of oxygen vacancies in transparent conductive oxide (TCO) films, one can assume that TCO layers in the metal/TiO 2 /TCO/metal assembly will be an additional source of oxygen vacancies for the TiO 2 film.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2014

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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.

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X-ray spectroscopic study of SrTiOx films with different interlayers

Cited by 15 publications

References 69 publications

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

Re-distribution of oxygen at the interface between γ-Al2O3 and TiN

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

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X-ray spectroscopic study of SrTiOx films with different interlayers

Cited by 15 publications

References 69 publications

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3−δ

Re-distribution of oxygen at the interface between γ-Al2O3 and TiN

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

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