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Enhanced electrical properties in sub-10-nm WO3 nanoflakes prepared via a two-step sol-gel-exfoliation method.

Zhuiykov S, Kats E - Nanoscale Res Lett (2014)

Bottom Line: The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques.CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method.It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Materials Science and Engineering Division, CSIRO, 37 Graham Road, Highett, VIC 3190, Australia.

ABSTRACT
The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques. CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method. It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

No MeSH data available.


Related in: MedlinePlus

I-V curves derived from CSFS-AFM images for sol-gel-developed WO3 and exfoliated Q2D WO3 nanoflakes. These I-V curves have been obtained by averaging the current values recorded independently for different DC sample bias.
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Figure 8: I-V curves derived from CSFS-AFM images for sol-gel-developed WO3 and exfoliated Q2D WO3 nanoflakes. These I-V curves have been obtained by averaging the current values recorded independently for different DC sample bias.

Mentions: Electrical CSFS-AFM measurements revealed and further proved the thickness-dependent properties of ultra-thin Q2D WO3. I-V curves for the sol-gel-developed WO3 nanostructures sintered at 550°C and for exfoliated ultra-thin Q2D WO3 nanoflakes sintered at 550°C and 650°C are presented in Figure 8. The current is measured by averaging the data values on the current image corresponding to the same voltage. There were neither significant oxidation nor reduction peaks recorded during scans. Non-linear behaviour for all samples was observed. This behaviour is typical for the semiconductor nature of the WO3[21]. However, the electrical performance showed significant difference between the sol-gel-developed WO3 nanostructures and exfoliated Q2D WO3 nanoflakes. It is clearly exhibited that the measured current for Q2D WO3 was about from 5 (650°C) to 10 (550°C) times higher than the measured current for the sol-gel-developed WO3 nanostructures. This fact confirms that the CFSF-AFM current originates from the local properties of the material at the tip-sample contact. The higher electrical activity and therefore greater currents for the exfoliated Q2D WO3 nanoflakes appeared to be more related to higher heterogeneous electron exchange rate caused by the quantum confinement effects within the few-layers limit [47]. Consequently, Q2D WO3 nanoflakes can offer reduced power dissipation because of smaller short channel effects [48]. Furthermore, the electrical measurements have also proved that the sintering temperature of 550°C is more suitable and superior for the development of Q2D WO3 nanoflakes with enhanced properties.


Enhanced electrical properties in sub-10-nm WO3 nanoflakes prepared via a two-step sol-gel-exfoliation method.

Zhuiykov S, Kats E - Nanoscale Res Lett (2014)

I-V curves derived from CSFS-AFM images for sol-gel-developed WO3 and exfoliated Q2D WO3 nanoflakes. These I-V curves have been obtained by averaging the current values recorded independently for different DC sample bias.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150682&req=5

Figure 8: I-V curves derived from CSFS-AFM images for sol-gel-developed WO3 and exfoliated Q2D WO3 nanoflakes. These I-V curves have been obtained by averaging the current values recorded independently for different DC sample bias.
Mentions: Electrical CSFS-AFM measurements revealed and further proved the thickness-dependent properties of ultra-thin Q2D WO3. I-V curves for the sol-gel-developed WO3 nanostructures sintered at 550°C and for exfoliated ultra-thin Q2D WO3 nanoflakes sintered at 550°C and 650°C are presented in Figure 8. The current is measured by averaging the data values on the current image corresponding to the same voltage. There were neither significant oxidation nor reduction peaks recorded during scans. Non-linear behaviour for all samples was observed. This behaviour is typical for the semiconductor nature of the WO3[21]. However, the electrical performance showed significant difference between the sol-gel-developed WO3 nanostructures and exfoliated Q2D WO3 nanoflakes. It is clearly exhibited that the measured current for Q2D WO3 was about from 5 (650°C) to 10 (550°C) times higher than the measured current for the sol-gel-developed WO3 nanostructures. This fact confirms that the CFSF-AFM current originates from the local properties of the material at the tip-sample contact. The higher electrical activity and therefore greater currents for the exfoliated Q2D WO3 nanoflakes appeared to be more related to higher heterogeneous electron exchange rate caused by the quantum confinement effects within the few-layers limit [47]. Consequently, Q2D WO3 nanoflakes can offer reduced power dissipation because of smaller short channel effects [48]. Furthermore, the electrical measurements have also proved that the sintering temperature of 550°C is more suitable and superior for the development of Q2D WO3 nanoflakes with enhanced properties.

Bottom Line: The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques.CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method.It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Materials Science and Engineering Division, CSIRO, 37 Graham Road, Highett, VIC 3190, Australia.

ABSTRACT
The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques. CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method. It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

No MeSH data available.


Related in: MedlinePlus