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Electronic Conduction in Ti/Poly-TiO2/Ti Structures.

Hossein-Babaei F, Alaei-Sheini N - Sci Rep (2016)

Bottom Line: Containing no interface energy barrier, Ti/poly-TiO2/Ti devices demonstrate high resistance ohmic conduction at biasing fields below 5 × 10(6) V.m(-1); higher fields drive the samples to a distinctly nonlinear and hysteretic low resistance status.The observed threshold is two orders of magnitude smaller than the typical resistance switching fields reported for the nanosized single grain memristors.This is consistent with the smaller activation energies reported for the IOV motion on the rutile facets than its interior.

View Article: PubMed Central - PubMed

Affiliation: Electronic Materials Laboratory, Electrical Engineering Department, K. N. Toosi University of Technology, Tehran 16317-14191, Iran.

ABSTRACT
Recent intensive investigations on metal/metal oxide/metal structures have targeted nanometric single grain oxides at high electric fields. Similar research on thicker polycrystalline oxide layers can bridge the results to the prior literature on varistors and may uncover novel ionic/electronic features originating from the conduction mechanisms involving grain boundaries. Here, we investigate electronic conduction in Ti/poly-TiO2-x/Ti structures with different oxygen vacancy distributions and describe the observed features based on the motion and rearrangement of the ionized oxygen vacancies (IOVs) on the grain facets rather than the grain interiors. Containing no interface energy barrier, Ti/poly-TiO2/Ti devices demonstrate high resistance ohmic conduction at biasing fields below 5 × 10(6) V.m(-1); higher fields drive the samples to a distinctly nonlinear and hysteretic low resistance status. The observed threshold is two orders of magnitude smaller than the typical resistance switching fields reported for the nanosized single grain memristors. This is consistent with the smaller activation energies reported for the IOV motion on the rutile facets than its interior. The presented model describes the observed dependence of the threshold field on the relative humidity of the surrounding air based on the lower activation energies reported for the hydroxyl-assisted IOV motion on the rutile facets.

No MeSH data available.


Related in: MedlinePlus

The structure of the samples.(a) The schematic diagram of the device structure; insets are the plan and cross-sectional micrographs of the TiO2 layer and (b) the schematic presentations of the different vacancy distributions in the A-samples and the B-samples.
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f1: The structure of the samples.(a) The schematic diagram of the device structure; insets are the plan and cross-sectional micrographs of the TiO2 layer and (b) the schematic presentations of the different vacancy distributions in the A-samples and the B-samples.

Mentions: Polycrystalline rutile layers, dominantly composed of {110}-faceted grains, are grown by the thermal oxidation of pure titanium chips. The fabrication of Ti/poly-TiO2−x/Ti samples (Fig. 1a) is completed by selectively depositing titanium thin film on the oxide surface. Representing the two different construction methods (see Methods) are two sample groups, A- and B-samples, which differ in their thermal annealing processes and IOV concentrations, as schematically shown in Fig. 1b.


Electronic Conduction in Ti/Poly-TiO2/Ti Structures.

Hossein-Babaei F, Alaei-Sheini N - Sci Rep (2016)

The structure of the samples.(a) The schematic diagram of the device structure; insets are the plan and cross-sectional micrographs of the TiO2 layer and (b) the schematic presentations of the different vacancy distributions in the A-samples and the B-samples.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940738&req=5

f1: The structure of the samples.(a) The schematic diagram of the device structure; insets are the plan and cross-sectional micrographs of the TiO2 layer and (b) the schematic presentations of the different vacancy distributions in the A-samples and the B-samples.
Mentions: Polycrystalline rutile layers, dominantly composed of {110}-faceted grains, are grown by the thermal oxidation of pure titanium chips. The fabrication of Ti/poly-TiO2−x/Ti samples (Fig. 1a) is completed by selectively depositing titanium thin film on the oxide surface. Representing the two different construction methods (see Methods) are two sample groups, A- and B-samples, which differ in their thermal annealing processes and IOV concentrations, as schematically shown in Fig. 1b.

Bottom Line: Containing no interface energy barrier, Ti/poly-TiO2/Ti devices demonstrate high resistance ohmic conduction at biasing fields below 5 × 10(6) V.m(-1); higher fields drive the samples to a distinctly nonlinear and hysteretic low resistance status.The observed threshold is two orders of magnitude smaller than the typical resistance switching fields reported for the nanosized single grain memristors.This is consistent with the smaller activation energies reported for the IOV motion on the rutile facets than its interior.

View Article: PubMed Central - PubMed

Affiliation: Electronic Materials Laboratory, Electrical Engineering Department, K. N. Toosi University of Technology, Tehran 16317-14191, Iran.

ABSTRACT
Recent intensive investigations on metal/metal oxide/metal structures have targeted nanometric single grain oxides at high electric fields. Similar research on thicker polycrystalline oxide layers can bridge the results to the prior literature on varistors and may uncover novel ionic/electronic features originating from the conduction mechanisms involving grain boundaries. Here, we investigate electronic conduction in Ti/poly-TiO2-x/Ti structures with different oxygen vacancy distributions and describe the observed features based on the motion and rearrangement of the ionized oxygen vacancies (IOVs) on the grain facets rather than the grain interiors. Containing no interface energy barrier, Ti/poly-TiO2/Ti devices demonstrate high resistance ohmic conduction at biasing fields below 5 × 10(6) V.m(-1); higher fields drive the samples to a distinctly nonlinear and hysteretic low resistance status. The observed threshold is two orders of magnitude smaller than the typical resistance switching fields reported for the nanosized single grain memristors. This is consistent with the smaller activation energies reported for the IOV motion on the rutile facets than its interior. The presented model describes the observed dependence of the threshold field on the relative humidity of the surrounding air based on the lower activation energies reported for the hydroxyl-assisted IOV motion on the rutile facets.

No MeSH data available.


Related in: MedlinePlus