09-01-2014, 01:27 PM
Synthesis and Field Emission Property of V2O5‚nH2O Nanotube Arrays
[attachment=59786]
ABSTRACT
Hydrated vanadium pentoxide (V2O5‚nH2O) nanotube arrays with outer diameters of 200 nm and lengths of
more than 5 μm have been synthesized via template-based physical wetting of V2O5 sols. The V2O5‚nH2O
nanotube arrays were characterized by scanning electron microscopy, X-ray diffraction, and high-resolution
transmission electron microscopy . The field emission (FE) of the V2O5‚nH2O nanotube arrays shows a turn-
on field of about 6.35 V/μm at a current density of 10 μA/cm2 and an emission current density up to 2.1
mA/cm2 at a field of 9.20 V/μm. The corresponding Fowler-Nordheim plot shows a linear behavior. These
features make the V2O5‚nH2O nanotube array a promising candidate for FE emitters.
Introduction
The effect of dimensionality and geometry on special
materials properties has been extensively investigated to meet
the demands of miniaturization and better performance of
electronic devices. Field emission (FE) based on both wide-
band gap and narrow-band gap materials with low-dimensional
and novel geometrical structures, such as C nanotubes,1 R-Fe2O3
nanowires,2 CuO nanobelts,3 well-oriented Cu2O film,4 ZnO
nanotubes,5 AlN nanoneedles,6 and so forth, has attracted prime
interest due to potential application in large-area flat panel
displays. These materials with novel structures, including well-
controlled electronic properties and low electron affinities,
become good candidates in other applications, such as thermo-
electric conversion and photovoltaic devices based on field
electron emission.4
Results and Discussion
Figure 1 shows the XRD patterns of the composite membrane
obtained by sol-wetting of the PC template and the PC
membrane. A peak can be seen at 2θ between 15° and 20°,
which is attributed to the PC membrane. Other peaks are
observed at 2θ between 20° and 30° with 2θ values of 7.306°,
22.51°, and 25.23°, which correspond to the (001), (302), and
(3
h03) diffraction planes of monoclinic V2O5‚3H2O crystal [No.
7-332], respectively. The diffraction peaks of the XRD pattern
can be indexed on the monoclinic V2O5‚3H2O, except that
originating from the PC membrane and based on the peak
broadening, the as-fabricated product is determined to be V2O5‚
3H2O nanocrystal. To see the one-dimensional nanoarray
structure of the as-grown sample, the PC membrane was
removed by being fired at 480 °C in air for 1 h through pyrolysis
and oxidation.18 The corresponding low-magnification SEM
image is shown in Figure 2a. From the image and its inset, which
is another SEM image of the sample, it can be revealed that
the as-grown V2O5‚nH2O nanostructure has one-dimensional
array morphology.
Conclusion
V2O5‚nH2O nanotubes with an average tip radius of 100 nm
have been synthesized via a simple route of template-based
physical wetting of V2O5 sols. The as-synthesized V2O5‚nH2O
nanotubes exhibit excellent field emission properties with a low
turn-on field of 6.35 V/μm and a maximum current density of
2.1 mA/cm2 at the field of 9.20 V/μm with linear F-N property.
All these features offer us a promising future for using V2O5‚
nH2O nanotubes as a competitive cathode material in field-
emission-based flat-panel displays.
[attachment=59786]
ABSTRACT
Hydrated vanadium pentoxide (V2O5‚nH2O) nanotube arrays with outer diameters of 200 nm and lengths of
more than 5 μm have been synthesized via template-based physical wetting of V2O5 sols. The V2O5‚nH2O
nanotube arrays were characterized by scanning electron microscopy, X-ray diffraction, and high-resolution
transmission electron microscopy . The field emission (FE) of the V2O5‚nH2O nanotube arrays shows a turn-
on field of about 6.35 V/μm at a current density of 10 μA/cm2 and an emission current density up to 2.1
mA/cm2 at a field of 9.20 V/μm. The corresponding Fowler-Nordheim plot shows a linear behavior. These
features make the V2O5‚nH2O nanotube array a promising candidate for FE emitters.
Introduction
The effect of dimensionality and geometry on special
materials properties has been extensively investigated to meet
the demands of miniaturization and better performance of
electronic devices. Field emission (FE) based on both wide-
band gap and narrow-band gap materials with low-dimensional
and novel geometrical structures, such as C nanotubes,1 R-Fe2O3
nanowires,2 CuO nanobelts,3 well-oriented Cu2O film,4 ZnO
nanotubes,5 AlN nanoneedles,6 and so forth, has attracted prime
interest due to potential application in large-area flat panel
displays. These materials with novel structures, including well-
controlled electronic properties and low electron affinities,
become good candidates in other applications, such as thermo-
electric conversion and photovoltaic devices based on field
electron emission.4
Results and Discussion
Figure 1 shows the XRD patterns of the composite membrane
obtained by sol-wetting of the PC template and the PC
membrane. A peak can be seen at 2θ between 15° and 20°,
which is attributed to the PC membrane. Other peaks are
observed at 2θ between 20° and 30° with 2θ values of 7.306°,
22.51°, and 25.23°, which correspond to the (001), (302), and
(3
h03) diffraction planes of monoclinic V2O5‚3H2O crystal [No.
7-332], respectively. The diffraction peaks of the XRD pattern
can be indexed on the monoclinic V2O5‚3H2O, except that
originating from the PC membrane and based on the peak
broadening, the as-fabricated product is determined to be V2O5‚
3H2O nanocrystal. To see the one-dimensional nanoarray
structure of the as-grown sample, the PC membrane was
removed by being fired at 480 °C in air for 1 h through pyrolysis
and oxidation.18 The corresponding low-magnification SEM
image is shown in Figure 2a. From the image and its inset, which
is another SEM image of the sample, it can be revealed that
the as-grown V2O5‚nH2O nanostructure has one-dimensional
array morphology.
Conclusion
V2O5‚nH2O nanotubes with an average tip radius of 100 nm
have been synthesized via a simple route of template-based
physical wetting of V2O5 sols. The as-synthesized V2O5‚nH2O
nanotubes exhibit excellent field emission properties with a low
turn-on field of 6.35 V/μm and a maximum current density of
2.1 mA/cm2 at the field of 9.20 V/μm with linear F-N property.
All these features offer us a promising future for using V2O5‚
nH2O nanotubes as a competitive cathode material in field-
emission-based flat-panel displays.