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Summary form only given. In this paper, we researched the uniformity properties of diode filed emission display matrix. The diode field emission display structure was prepared by screen-printing and vacuum coating technology. Matrix points are formed at the intersection of cathode and anode stripes. Emission currents and images were tested in the d.c. mode and pulse mode. For improving the emission uniformity and stability, we modified the cathode structure based on electric field analysis. Due to the electrical fields are strongly enhanced at the edges of the electrode, narrower carbon nanotube emitter stripes were printed only on one edges of the cathode electrodes, and insulated barrier walls with same height were close printed at the same edge of the emitter stripes. This structure could improve the vertical emission and limit the sidelong emission because of edge field effect. We also introduced plasma etching treatment to modify the surface morphology and improve the field emission properties. A diode field emission display devices with 30×30 matrix showed a stable image. The emission uniformity and stability was improved.

Cu/sub 2/S nanowires with different morphology were fabricated under different preparation conditions. It was found that the pre-treatment of copper substrate played an important role in the growth of Cu/sub 2/S nanowires. Pre-heat treatment (such as oxidation) was found to be the key step for obtaining large area of nanowires. Also, the field emission characteristics of nanowires prepared under different conditions were studied in this work.

The distribution of electric field of aligned carbon-nanotube-bundle arrays was simulated. The field enhancement factors (/spl beta/) of the top of the carbon nanotubes of the arrays were calculated. It was found that the carbon nanotube films having the cone-shape bundle have nanotubes with higher field enhancement factors. This can explain the experimental findings.

Films of aligned cupric oxide-nanobelts have been prepared in an aqueous solution at room temperature. Field electron emission characteristics, including emission current-applied field characteristic, emission site distribution and emission current stability have been studied.

In this report, details are given of our recent experimental study of using carbon nanotubes (CNTs) as cathode of the luminescent tubes. The CNT film is synthesized by thermal chemical vapor deposition. Two kinds of luminescent tubes that have different gaps have been fabricated. The luminescent tube with 0.1mm gap has a low threshold voltage of about 780V and high emission current of 300 microA when the gate voltage is 970V. The DC power consumption of the luminescent tube with a 0.1mm gap is approximately 1.12W. The results show that the CNTs are very good emission sources and suitable for application in the luminescent tube.

In this study, we present a prototype of lighting element in which a carbon-containing field emission material is used as the cathode. The operating characteristics, i.e. current-voltage characteristics, current stability, luminance and lifetime of the lighting element are tested. By applying high-voltage phosphor, a maximum brightness of 10000cd/m(2) has been recorded and a lighting element under lifetime test has been operating in DC driving mode for over 2500h without decay in emission current and brightness. These results imply that the prototype lighting element is suitable for commercial application.

Gated field emission electron sources of amorphous diamond (a-D) coated Si tips and a-D diodes on a rough Si substrate were studied, detailing the deposition and characterization of the thin film, the fabrication processes and the emission behavior of the electron sources. Mechanisms responsible for the emission process of the a-D coated devices are proposed. A comparison of the field emission performance of the two types of devices is presented. In addition, future improvements of the a-D diode on a rough Si cathode are discussed.

The study of field electron energy spectra from amorphous carbon-nitride (a-CN) films is essential to understand the mechanism of field emission from this promising material. In this work, the electron energy spectrum is studied by measuring the distribution of electron field emitted from individual emitting sites. The spectra are recorded at different electrical fields. It is found that the peak shift as well as the half-width increase with increasing applied fields. Furthermore, multi-peak features are observed at the low-energy side of the spectra. It is assumed that these peaks might originate from the interband states of a-CN film. We propose that although the emission mainly originates from current injection into conduction band of a-CN film, the electrons may also be emitted from interband states.

We report the first observation of ultraviolet superfluorescence (SF) from oxygen vacancies in WO3−x nanowires at room temperature, and of picosecond-scale energy transfer between emission centers (oxygen vacancies) in a plane. A theoretical development from Dicke’s model leads to general formulation for a two-dimensional system, and is applied to explain the energy transfer process. The results demonstrate a possibility to generate ultrafast pulse of ultraviolet light through SF from a localized ensemble of defect states.

The photoluminescence spectra of WO3−x nanowire networks, WO3 nanowires networks, and the bulk phase WO3 powder have been investigated under the continuous wave excitation light at 320nm. Two broad band emissions in spectrum of WO3−x nanowire networks are observed including the ultraviolet-visible (UV-vis) emission centered at 395nm and the blue emission centered at 467nm. The authors demonstrate that the blue emission in WO3−x nanowire networks is due to band-band transition of the bulk phase WO3 and the UV-vis emission is attributed to the state of oxygen vacancies, which are characterized by using scanning electron microscopy and x-ray photoelectron spectroscopy. The UV-vis emission exhibits a strong dependence on the excitation wavelength, while the blue emission is independent of the excitation wavelength. The UV-vis emission is discussed in configuration-coordinate diagram of a localized state of oxygen vacancies. In particular, this state of defect is a high-lying resonant state in the conduction band of WO3.

Tungsten trioxide (WO3) nanowires were synthesized by thermal evaporation of tungsten powder in two steps: tungsten suboxide (WO3−x) nanowires were synthesized, and then oxidized in O2 ambient and transformed into WO3 nanowires. Raman spectroscopy was applied to study the thermochromic phase transition of one-dimensional WO3 nanowires. From the temperature dependence of the characteristic mode at 33cm−1 in WO3, the phase transition temperature was determined. It was found that the phase transition of WO3 nanowires was reversible and the phase transition temperatures were even lower than that of WO3 nanopowder.

Single crystalline silicon carbide (SiC) nanowires were grown directly on the surface of bulk SiC ceramic substrate in a catalyst-assisted thermal heating process. The morphology of the nanowire film and the diameter of nanowires were found to be sensitive to the thickness of catalyst film and both of them had a strong effect on field emission performance. Very low turn-on and threshold fields for electron emission were observed with SiC nanowires of small diameter. A model is proposed to qualitatively explain the field emission findings, which assumes the occurrence of an insulator-to-metal-like transition in a field emitting nanowire.

A technique involving a combination of using self-assembled nanomask and anisotropic plasma etching is developed for fabricating vertically aligned single-crystalline Si nanowires (SiNWs). The SiNWs are shown to have excellent field emission performance with the turn-on field as low as 0.8MV∕m and the threshold field being 5.0MV∕m. In addition, an emission current density of 442mA∕cm2 can be obtained at an applied field of ∼14MV∕m. The technique is easily employed to fabricate arrays of SiNW-based field emission microtriodes. Mechanisms are proposed to explain the formation of the SiNWs and the observed field emission properties.

Large-area, quasialigned nanotips of tungsten oxide have been grown by a two-step high-temperature, catalyst-free, physical evaporation deposition process. The tungsten oxide nanotips are single crystalline with growth direction of [010]. The tungsten oxide nanotips exhibit excellent field-emission properties with a low threshold field (for an emission current density of 10mA∕cm2) ∼4.37MV∕m and uniform emission from the entire arrays, as well as high time stability. These results make tungsten oxide nanotip arrays a competitive candidate for field-emission displays.

We report procedure with use of self-assembled silicon carbide (SiC) nanomasks for preparation of ultrahigh-density Si nanotips. Si nanotips with SiC apex may be firstly prepared in a CH4∕H2 plasma treatment and in a subsequent H2 plasma etching a SiC apex may be converted into an amorphous silicon (a-Si) one with an additional function of sharpening the nanotips. A comparative study of the field electron emission from the Si nanotips with apexes of SiC, a-Si and pure Si is carried out, and shows that nanotips with a-Si apexes have not only the highest field enhancement factor but also the best emission uniformity. The physical origins for the above two improvements in field emission are discussed.

Effects of pulsed and continuous light illumination on field emission from CuO nanobelt arrays have been studied by using a transparent anode technique. It is found that, at low-field emission current level, the field emission current generally increases under a pulsed irradiation; at an emission current level of 1.1μA, a 19% increase in emission current was recorded. The photoinduced current increase is reduced with increasing emission current and is undetectable when the emission current is higher than 15μA. On the other hand, a long time illumination of the sample decreases the field emission current. Possible physical mechanisms behind the observed phenomena are discussed.

In the present work, we report our finding of ultra-high emission current from a single CNT emitter. This work enhances the understanding of the field emission characteristics of CNT emitters and its potential application as ultra-bright electron source.