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1.
Electronic properties and field emission of carbon nanotube films treated by hydrogen plasma 总被引:1,自引:0,他引:1
Large-scale and very even multi-wall carbon nanotube (MWNT) films have been obtained at room temperature by an electrophoresis deposition technique. The characterization, by means of scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and micro-Raman spectroscopy, shows that the MWNTs with hydrogen-plasma (HP) treatment are covered by onion-like nanolumps, and three-dimensional multiple-way-connected nanotube webs are formed. The electronic property of the treated MWNT film is converted from semiconducting to metallic. The field-emission test indicates that the HP-treated MWNT film has a low threshold of 1.1 V/m (at 0.1 A/cm2), a high emission light spot density of about 105 cm-2, and a stable and suitable emission current. The conversion mechanism of the treated carbon nanotube structure and the reason for the change of the electronic and field-emission characteristics of the MWNT films are discussed. PACS 81.07.De; 82.33.Xj; 85.45.Db 相似文献
2.
Embedding of carbon nanotubes in conducting polymeric matrices for various nanocomposites material is now a popular area. In this article, a concise chemical method has been described for the preparation of homogeneous nanocomposite of multi-walled carbon nanotube (MWNT)/polyaniline (PANI) by electrochemical codeposition. For this we functionalized the MWNTs via the diazotization reaction. This helped to disperse the nanotubes in aniline. The composite films were dispersed Pt by electrodeposition technique. The presence of MWNTs and platinum in the composite films was confirmed by XRD analysis and transmission electron microscopy (TEM). Four-point probe investigations revealed that the MWNT/PANI composite films exhibited a good conductivity. Cyclic voltammograms (CV) showed that Pt-modified MWNT/PANI composite films perform higher electrocatalytic activity and better long-term stability than Pt-modified pure PANI film toward formic acid oxidation. The results imply that the MWNT/PANI composite films as a promising support material improves the electrocatalytic activity for formic acid oxidation greatly. 相似文献
3.
The good field-emission properties of carbon nanotubes coupled with their high mechanical strength, chemical stability, and
high aspect ratio, make them ideal candidates for the construction of efficient and inexpensive field-emission electronic
devices. The fabrication process reported here has considerable potential for use in the development of integrated radio-frequency
amplifiers or field-emission-controllable cold-electron guns for field-emission displays. This fabrication process is compatible
with currently used semiconductor-processing technologies. Micropatterned vertically aligned carbon nanotubes were grown on
a planar Si surface or inside trenches, using chemical vapor deposition, photolithography, pulsed-laser deposition, reactive
ion etching, and the lift-off method. This carbon-nanotube fabrication process can be widely applied for the development of
electronic devices using carbon-nanotube field emitters as cold cathodes and could revolutionize the area of field-emitting
electronic devices.
Received: 30 August 2001 / Accepted: 3 September 2001 / Published online: 20 December 2001 相似文献
4.
T. A. Tumareva 《Physics of the Solid State》1999,41(4):660-663
A study has been made of the field-emission characteristics of cerium and BaO films on W within a broad range of field-emission
currents and fields. An anomalous broadening of the spectra and a deviation of Fowler-Nordheim characteristics from linearity
have been revealed for high (above 109 A/m2) field-emission current densities. The dependence of this anomalous behavior of field-emission characteristics on the work
function and topography of the surface has been investigated. Possible reasons for the observed phenomena are discussed.
Fiz. Tverd. Tela (St. Petersburg) 41, 732–735 (April 1999) 相似文献
5.
F. Sánchez M.V. García-Cuenca C. Ferrater M. Varela 《Applied Physics A: Materials Science & Processing》2002,75(3):381-385
We report on the epitaxial growth of yttria-stabilised zirconia (YSZ) buffer layers on X-cut LiNbO3 (LNO) single crystals by pulsed laser deposition. Despite the low chemical stability of the substrates at high temperature,
high quality fully reproducible films were obtained over a relatively broad range of processing conditions. The films were
(00h) out-of-plane single oriented and the in-plane edge of the YSZ unit cell was aligned with the polar axis of the LNO.
However, the YSZ deposition also promoted the formation of the compound LiNb3O8. This compound is epitaxial and located at the interface. The homogeneous YSZ film presents a uniform surface, free of outgrowths
and with a low roughness. These characteristics are suitable for the epitaxial growth of other oxides, as has been demonstrated
with the preparation of YBa2Cu3O7/CeO2/YSZ/LNO heterostructures. The superconducting YBa2Cu3O7 films were epitaxial, with the c axis perpendicular to the surface and single in-plane orientation, and presented good transport
properties (critical temperatures around 86 K and critical current densities close to 106 A/cm2 at 77 K).
Received: 5 April 2001 / Accepted: 30 July 2001 / Published online: 30 October 2001 相似文献
6.
Vertically aligned one-dimensional ZnO nanowire arrays have been synthesized by a hydrothermal method on sol–gel derived ZnO films. Sol–gel derived ZnO films and corresponding ZnO nanowire arrays have been characterized by X-ray diffraction and field-emission scanning electron microscopy. The effect of sol–gel derived ZnO film surface on the morphology of ZnO nanowire arrays has been investigated. The authors suggest from our investigation that sol–gel derived ZnO films affect the growth of one-dimensional ZnO nanostructures. Not only crystalline ZnO films but also amorphous ones can act as a scaffold for ZnO nucleus. Tilted ZnO micro-rods are grown on ZnO gel films, whereas vertically aligned ZnO nanowire arrays are grown on nanometer-sized ZnO grains. The average diameter of ZnO nanowire arrays are correlated strongly with the grain size of sol–gel derived ZnO films. 相似文献
7.
J.H. Chen Z.P. Huang D.Z. Wang S.X. Yang J.G. Wen Z.F. Ren 《Applied Physics A: Materials Science & Processing》2001,73(2):129-131
Polypyrrole/carbon nanotube nanoscale composites were successfully fabricated by electrochemical deposition of polypyrrole
over each of the carbon nanotubes in well-aligned large arrays. The thickness of the polypyrrole coating can be easily controlled
by the value of the film-formation charge. For both thin (low film-formation charge) and thick (high film-formation charge)
films, the polypyrrole coating on the surface of each nanotube is very uniform throughout the entire length, as observed by
transmission electron microscopy.
Received: 2 May 2001 / Accepted: 4 May 2001 / Published online: 20 June 2001 相似文献
8.
9.
A. K. Murugesh A. Uthayanan C. Lekakou 《Applied Physics A: Materials Science & Processing》2010,100(1):135-144
This paper contains an in-depth analysis of the electrophoresis of multi-wall carbon nanotubes (MWNTs) in liquid epoxy where
electrophoresis experiments under DC and AC fields were carried out for five different types of multi-wall carbon nanotubes
(MWNTs). DC electrophoresis and particle image velocimetry were used to determine the electrophoretic particle mobility and
zeta potential, where the MWNTs with the largest outer diameter and length led to the highest mobility values. The orientation
and agglomeration of MWNTs into “striation” lines under AC electrophoresis were investigated by analysing the hue, saturation
and intensity of the transmitted polarised light under microscope, following a schedule of step-wise applied voltage in the
range of 0 to 100 V. Plots of hue and saturation as a function of the applied voltage were used to assess the degree of orientation
and density of orientated MWNT structures, respectively, and to determine an optimum AC electric field value for the orientation
of a specific MWNT type by electrophoresis. 相似文献
10.
In this work we report laterally aligned multi-walled carbon nanotube (MWNT) by an electric field during growth. The MWNTs were selectively grown between lateral sides of the catalytic metals on predefined electrodes by chemical-vapor deposition. The electric field distribution for various geometries was simulated using Maxwell 2D simulation in order to realize better alignment of laterally grown carbon nanotubes (CNTs). The experimental results show that the electric field direction at the vicinity of catalyst and nanotubes-substrate interactions are principal factor in aligning CNTs laterally. 相似文献