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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 effect of relative humidity change on the current vs. voltage characteristics of the samples.The diagrams are recorded for an A-sample (a) and a B-sample (b) in clean air at the stated relative humidity levels at room temperature. The inset in (b) magnifies the low voltage region of the diagram to clarify its independence from the relative humidity level.
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f5: The effect of relative humidity change on the current vs. voltage characteristics of the samples.The diagrams are recorded for an A-sample (a) and a B-sample (b) in clean air at the stated relative humidity levels at room temperature. The inset in (b) magnifies the low voltage region of the diagram to clarify its independence from the relative humidity level.

Mentions: The function of the adsorbed water monomers in facilitating the IOV motion at the grain boundaries is studied by observing the effect of atmospheric humidity change on the I–V diagrams of the A- and B-samples. The I–V characteristics of the samples are plotted in air at different relative humidity (RH) levels. The results are presented in Fig. 5a,b. While the conduction in the A-sample remains almost unaffected by the humidity change, that in the B-sample increases with the RH level in the surrounding atmosphere. Figure 5b depicts considerable reduction in the switching field with respect to the increased humidity. The observed effect is consistent with the low activation energy reported for the H2O molecule-assisted oxygen vacancy motion on the rutile {110} surfaces4649. Considering the dense microstructure of the titanium oxide layers grown by thermal oxidation56 as well as the lack of humidity-caused change in the HRS of the device (see the inset in Fig. 5b), the effect of humidity is a novel observation distinct from the surface conduction resulting from adsorbed water layers in the porous dielectric materials57.


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

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

The effect of relative humidity change on the current vs. voltage characteristics of the samples.The diagrams are recorded for an A-sample (a) and a B-sample (b) in clean air at the stated relative humidity levels at room temperature. The inset in (b) magnifies the low voltage region of the diagram to clarify its independence from the relative humidity level.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: The effect of relative humidity change on the current vs. voltage characteristics of the samples.The diagrams are recorded for an A-sample (a) and a B-sample (b) in clean air at the stated relative humidity levels at room temperature. The inset in (b) magnifies the low voltage region of the diagram to clarify its independence from the relative humidity level.
Mentions: The function of the adsorbed water monomers in facilitating the IOV motion at the grain boundaries is studied by observing the effect of atmospheric humidity change on the I–V diagrams of the A- and B-samples. The I–V characteristics of the samples are plotted in air at different relative humidity (RH) levels. The results are presented in Fig. 5a,b. While the conduction in the A-sample remains almost unaffected by the humidity change, that in the B-sample increases with the RH level in the surrounding atmosphere. Figure 5b depicts considerable reduction in the switching field with respect to the increased humidity. The observed effect is consistent with the low activation energy reported for the H2O molecule-assisted oxygen vacancy motion on the rutile {110} surfaces4649. Considering the dense microstructure of the titanium oxide layers grown by thermal oxidation56 as well as the lack of humidity-caused change in the HRS of the device (see the inset in Fig. 5b), the effect of humidity is a novel observation distinct from the surface conduction resulting from adsorbed water layers in the porous dielectric materials57.

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