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Novel electroforming-free nanoscaffold memristor with very high uniformity, tunability, and density.

Lee S, Sangle A, Lu P, Chen A, Zhang W, Lee JS, Wang H, Jia Q, MacManus-Driscoll JL - Adv. Mater. Weinheim (2014)

Bottom Line: The strategy is to design vertical interfaces using two structurally incompatible oxides, which are likely to generate a high-concentration oxygen vacancy.Non-linear electroresistance at room temperature is demonstrated using these nano scaffold devices.The resistance variations exceed two orders of magnitude with very high uniformity and tunability.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.

No MeSH data available.


Formation of Vo¨ at vertical heterointerfaces due to the structural discontinuity of SrTiO3 matrix and Sm2O3 nanocolumn. a) “Nano-comb”-like spontaneous phase ordering in cross-sectional-view of nanoscaffold SrTiO3-Sm2O3, as revealed by cross-sectional STEM HAADF image. b) High-resolution HAADF image of vertical interface of SrTiO3 matrix and Sm2O3 nanocolumn in cross-sectional-view. c) Crystallographic modelling of vertical interface between SrTiO3 and Sm2O3. d) STEM HAADF plan-view image of SrTiO3 matrix and Sm2O3 nanocolumn. e) Measured concentration profile of Sm (green line), Ti (grey line) and O (blue circles) elements across the vertical interface using EELS. Shown in red circles is the calculated EELS signal of O element.
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fig03: Formation of Vo¨ at vertical heterointerfaces due to the structural discontinuity of SrTiO3 matrix and Sm2O3 nanocolumn. a) “Nano-comb”-like spontaneous phase ordering in cross-sectional-view of nanoscaffold SrTiO3-Sm2O3, as revealed by cross-sectional STEM HAADF image. b) High-resolution HAADF image of vertical interface of SrTiO3 matrix and Sm2O3 nanocolumn in cross-sectional-view. c) Crystallographic modelling of vertical interface between SrTiO3 and Sm2O3. d) STEM HAADF plan-view image of SrTiO3 matrix and Sm2O3 nanocolumn. e) Measured concentration profile of Sm (green line), Ti (grey line) and O (blue circles) elements across the vertical interface using EELS. Shown in red circles is the calculated EELS signal of O element.

Mentions: To explore the possible origin of the intriguing, new nonlinear electroresistance phenomenon we have observed in the nanoscaffold films, we investigated the atomic structure at the vertical interfaces. Figure3a is a scanning transmission electron microscopy (STEM) high-angle annular dark-field (HAADF) image of nanoscaffold SrTiO3-Sm2O3 films in cross-sectional-view, showing spontaneous phase ordering. The 100-nm-long bright nanocolumns are very straight. The dark and bright contrast regions of ∼10-nm-width are alternatively separated like a “nano-comb”. Due to atomic number Z-contrast nature of HAADF imaging, the dark and bright areas in the image correspond to the SrTiO3 and Sm2O3, respectively. The result was further confirmed by energy-dispersive x-ray spectroscopy (EDS) (Figure S6). The epitaxial Sm2O3 phase grows on the Nb-doped SrTiO3 substrate with a 45o in-plane rotation to minimize their lattice mismatch,19–21 which was also proven by an x-ray diffraction phi-scan (Figure S7). The reciprocal space maps also reveal that the Sm2O3 peak of SrTiO3-Sm2O3 nanoscaffold films is much narrower than that of single Sm2O3 films (Figure S8). This indicates that, in the nanoscaffold film, both Sm2O3 and SrTiO3 are well crystallized and their lattice constants are uniform through the thickness of the film.19–21


Novel electroforming-free nanoscaffold memristor with very high uniformity, tunability, and density.

Lee S, Sangle A, Lu P, Chen A, Zhang W, Lee JS, Wang H, Jia Q, MacManus-Driscoll JL - Adv. Mater. Weinheim (2014)

Formation of Vo¨ at vertical heterointerfaces due to the structural discontinuity of SrTiO3 matrix and Sm2O3 nanocolumn. a) “Nano-comb”-like spontaneous phase ordering in cross-sectional-view of nanoscaffold SrTiO3-Sm2O3, as revealed by cross-sectional STEM HAADF image. b) High-resolution HAADF image of vertical interface of SrTiO3 matrix and Sm2O3 nanocolumn in cross-sectional-view. c) Crystallographic modelling of vertical interface between SrTiO3 and Sm2O3. d) STEM HAADF plan-view image of SrTiO3 matrix and Sm2O3 nanocolumn. e) Measured concentration profile of Sm (green line), Ti (grey line) and O (blue circles) elements across the vertical interface using EELS. Shown in red circles is the calculated EELS signal of O element.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4225682&req=5

fig03: Formation of Vo¨ at vertical heterointerfaces due to the structural discontinuity of SrTiO3 matrix and Sm2O3 nanocolumn. a) “Nano-comb”-like spontaneous phase ordering in cross-sectional-view of nanoscaffold SrTiO3-Sm2O3, as revealed by cross-sectional STEM HAADF image. b) High-resolution HAADF image of vertical interface of SrTiO3 matrix and Sm2O3 nanocolumn in cross-sectional-view. c) Crystallographic modelling of vertical interface between SrTiO3 and Sm2O3. d) STEM HAADF plan-view image of SrTiO3 matrix and Sm2O3 nanocolumn. e) Measured concentration profile of Sm (green line), Ti (grey line) and O (blue circles) elements across the vertical interface using EELS. Shown in red circles is the calculated EELS signal of O element.
Mentions: To explore the possible origin of the intriguing, new nonlinear electroresistance phenomenon we have observed in the nanoscaffold films, we investigated the atomic structure at the vertical interfaces. Figure3a is a scanning transmission electron microscopy (STEM) high-angle annular dark-field (HAADF) image of nanoscaffold SrTiO3-Sm2O3 films in cross-sectional-view, showing spontaneous phase ordering. The 100-nm-long bright nanocolumns are very straight. The dark and bright contrast regions of ∼10-nm-width are alternatively separated like a “nano-comb”. Due to atomic number Z-contrast nature of HAADF imaging, the dark and bright areas in the image correspond to the SrTiO3 and Sm2O3, respectively. The result was further confirmed by energy-dispersive x-ray spectroscopy (EDS) (Figure S6). The epitaxial Sm2O3 phase grows on the Nb-doped SrTiO3 substrate with a 45o in-plane rotation to minimize their lattice mismatch,19–21 which was also proven by an x-ray diffraction phi-scan (Figure S7). The reciprocal space maps also reveal that the Sm2O3 peak of SrTiO3-Sm2O3 nanoscaffold films is much narrower than that of single Sm2O3 films (Figure S8). This indicates that, in the nanoscaffold film, both Sm2O3 and SrTiO3 are well crystallized and their lattice constants are uniform through the thickness of the film.19–21

Bottom Line: The strategy is to design vertical interfaces using two structurally incompatible oxides, which are likely to generate a high-concentration oxygen vacancy.Non-linear electroresistance at room temperature is demonstrated using these nano scaffold devices.The resistance variations exceed two orders of magnitude with very high uniformity and tunability.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.

No MeSH data available.