Field Emission Display Research Articles

Fabrication Research and Property of Double Cold Cathode for the Field Emission Display Panel

With the precise photolithography process and simple screen-printing technique, the double cold cathode structure was fabricated on the cathode plate. The indium tin oxide (ITO) film coated over the cathode plate surface was etched to form bar ITO stripes, which was used as the cathode electrode. The one ITO group was composed of two parallel bar ITO stripes, on which the screen-printed carbon nanotube paste was employed to form the field emitter. The covering layer was also fabricated by the solidified insulation slurry with the pre-determined patterns. The phosphor prepared on the anode plate was utilized to form the panel image. The sealed field emission display panel with double cold cathode structure showed high panel luminous brightness, better field emission characteristics and good emission uniformity.

Large Area Graphene on Polymer Films for Transparent and Flexible Field Emission Device

ABSTRACTLarge scale fabrication of graphene over transparent flexible polymer, Polyethelyne tetrapthalate (PET), and its application in flexible field emission display is reported here. We used Cu foil (~160 mm x 60 mm) to grow graphene by thermal chemical vapor deposition process and transfer the graphene over a polymer using a straightforward hot press lamination technique. The fabrication method is facile as there is no rigorous chemical process involved and the process is also applicable towards the fabrication of large scale graphene over a wide range of transparent flexible substrates for foldable micro-electronics applications. Further, we demonstrate the application of graphene/PET polymer film as anode of transparent flexible field emission display device. The device shows low turn-on voltage ~ 1.75V/μm and high current density of ~ 65μA/cm2 with field enhancement factor (β) ~1000.

Fabrication of Combined Type Insulation Wall in a Field Emission Display with Carbon Nanotube Emitters

Using insulation slurry as material, the combined type insulation wall was developed with the high-effective screen-printing process. Two parts were mainly included for the combined type insulation wall, which was the lower insulation wall prepared on the cathode panel and the upper insulation wall fabricated on the anode panel, respectively. The fabricated combined type insulation wall possessed better insulation performance, and was used to separate the cathode and anode panel. Using carbon nanotube as cathode material, the field emission display with the combined type insulation wall was fabricated, and the detailed manufacture process was also presented. The sealed field emission display showed high luminance brightness, stable emission current and good field emission properties.

Study on the Fabrication of Compound Cold Cathode Electrode in a Field Emission Display

With photolithography process and screen printing technique, the compound cold cathode electrode was developed on the cathode glass plate for improving the field emission ability and emission uniformity of CNT cathode. The compound cold cathode electrode mainly consisted of the indium tin oxide (ITO) blocks which was the divided ITO thin film, the bar silver stripes fabricated by the solidified silver slurry and the cathode insulation layer with good insulation performance. Carbon nanotubes were prepared to form the field emitters, and the diode type field emission display (FED) was fabricated. The manufacture process was also presented in detail. The vacuum sealed FED exhibited better field emission characteristic, low operating voltage and high display brightness.

Carbon Nanotubes as Field Emitter

Carbon nanotubes (CNTs) have recently emerged as a promising material of electron field emitters. They exhibit extraordinary field emission properties because of their high electrical conductivity, high aspect ratio "needle like" shape for optimum geometrical field enhancement, and remarkable thermal stability. In this Review, we emphasize the estimation and influencing factors of CNTs' emission properties, and discuss in detail the emission properties of macroscopic CNT cathodes, especially fabricated by transplant methods, and describe recent progress on understanding of CNT field emitters and analyze issues related to applications of CNT based cold cathodes in field emission display (FED). We foresee that CNT-FED will take an important place in display technologies in the near future.

Hydrothermal synthesis of core-shell structured PS@GdPO4:Tb3+/Ce3+ spherical particles and their luminescence properties

AbstractNon-aggregated spherical polystyrene (PS) particles were coated with GdPO4:Tb3+/Ce3+ phosphor layers by a conventional hydrothermal synthesis using poly(vinylpyrrolidone) (PVP) as an additive without further annealing treatment. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), as well as luminescence decay experiments were used to characterise the resulting core-shell structured PS@GdPO4:Tb3+/Ce3+ samples. The results of XRD indicated that the PS particles were successfully coated with the GdPO4:Tb3+/Ce3+ phosphor layers, which could be further verified by the images of FESEM. Under ultraviolet excitation, the PS@GdPO4:Tb3+/Ce3+ phosphors show Tb3+ characteristic emission, i.e. 5D4-7FJ (J = {6, 5, 4, 3}) emission lines with green emission 5D4-7F5 (543 nm) as the most prominent group. The core-shell phosphors so obtained have potential applications in field emission display (FED) and plasma display panels (PDP).

Characteristics of a Triode Field Emission Display Panel with the Suspension Gate Structure

With the effective screen-printing technique and high-temperature sintering process, the suspersion gate structure was developed. The silver slurry was printed on the gate substrate to form the gate electrode. Using carbon nanotube as cold field emitter, the triode field emission display (FED) panel was fabricated, and the detailed manufacture process was also presented. The anode back plane, the cathode back plane and spacer combined to device room, in which the suspension gate structure would be included. The distance between the gate electrode and carbon nanotube cathode could be reduced, which could decrease the device manufacture cost because of the small gate voltage. The modulation of emitted electron by the gate voltage would be confirmed, and the field emission characteristics was measured. The sealed FED panel with simple fabrication process and designed structure possessed better field emission uniformity, high display brightness and field emission perofrmance.

Study of Vacuum-Sealed Field Emission Display Device with Discrete Anode Sub-Pixel Layer

Using carbon nanotube as field emitter, the diode-structure field emission display device was fabricated with conventional sintering techniques. With the precise photolithography process, the indium tin oxide film coated on the anode faceplate surface was etched to form the bar anode electrode. Using the screen-priinting technology, the insulation slurry was prepared on the bar anode electrode surface to form the anode separate layer. So the discrete anode sub-pixels layer structure was developed. For the vacuum-selaed FED device, the typical field emission characteristics were measured and the displayed dot matrix image was also presented. The fabricated FED device with discrete anode sub-pixel layer possessed higher dispaly image brightness, good image disnlay performance and better field emission characteristics.

Tungsten Oxide Nanowires Grown on Carbon Cloth as a Flexible Cold Cathode

Figure 1 . a) Optical images of the carbon cloth with TONWs, left-inset and right-inset show the optical images of a carbon cloth with TONWs under slight bending and severe bending, respectively. b,c) SEM images of the carbon cloth before and after growing TONWs, respectively. Inset [∗] X. H. Zhang , Y. Z. Cao , X. Xiao , W. M. Sun , Prof. Y. H. Gao , Prof. J. Zhou , Prof. Z. L. Wang Wuhan National Laboratory for Optoelectronics (WNLO) and College of Optoelectronic Science and Engineering Huazhong University of Science and Technology (HUST) Wuhan, 430074 (P. R. China) E-mail: jun.zhou@mail.hust.edu.cn; zhong.wang@mse.gatech.edu L. Gong , Prof. J. Chen Instrumental Analysis & Research Center Sun Yat-sen University Guangzhou, 510275 (P. R. China) K. Liu , Prof. X. J. Hu School of Power and Mechanical Engineering Wuhan University Wuhan, 430072 (P. R. China) Prof. Z. L. Wang School of Materials Science and Engineering Georgia Institute of Technology Atlanta, Georgia 30332-0245 (USA) Nanowire arrays for fi eld emission have attracted a lot of interest in the last few years because of numerous applications such as fl at-panel displays, X-ray radiotherapy, microwave amplifi ers, and vacuum microelectronic devices. [ 1 , 2 ] The growth of fi eld emitters on fl exible substrates may open up numerous fi elds of applications such as roll-up fi eld emission displays (FEDs), [ 3 ]

Preparation and Field Emission Properties of Ag-CNTs by Electroless Plating

Carbon nanotubes (CNTs) demonstrate attractive characteristics as cold cathode emitters for high aspect ratio, small radius of curvature, high mechanical strength and chemical stability. In this article, Ag-CNTs were prepared by a series of processes including acid-treating, sensitizing, activating and electroless plating. Then Ag-CNTs cathode were sucessfully fabricated by electrophoresis deposition (EPD) method. The morphologies of Ag-CNTs cathode and pristine CNTs cathode were observed by scanning electron microscopy (SEM). The results showed that the field emission properties of Ag-CNTs cathode were better than pristine CNTs cathode, for presenting lower turn-on field, larger emission current density, more stabilization and longer lifetime. Thus it can be seen that the Ag-CNTs cathode can improve the characteristics of carbon nanotubes field emission display (CNT-FED).

Experimental Preparation and Properties of Modified CNT Field Emitters for the Field Emission Display Panel

Carbon nanotube used as the cathode material, the diode-type field emission display panel was developed with low-cost screen-printing method and precise photolithography process. The modified CNT field emitter was fabricated for improving the field emission characteristic, and the detailed fabrication process was also presented. The indium-tin-oxide film on the cathode back-plane was divided to form the CNT cathode electrode, and the insulation slurry was screen-printed to form the insulation layer. Field emission characteristic of whole display device was measured. The sealed field emission display panel showed good emission properties and high display image brightness.

Pattern Growth and Field Emission Characteristics of Flower-Like RuO2 Nanostructures

A flower-like RuO2 nanostructure was selectively synthesized on a Si substrate by metal organic chemical vapor deposition (MOCVD). Bis(ethylcyclopentadienyl) ruthenium(II), Ru[(C2H5)C5H4]2, was shower sprayed onto the Si substrate with oxygen gas. Prior to the growth of the flower-like RuO2 nanostructure, patterns of Al and Fe films were deposited on the Si substrate by photolithography and electron beam (e-beam) evaporation deposition. The synthesized flower-like RuO2 nanostructures were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), and micro-Raman spectroscopy. The results indicated that the flower-like nanostructures were RuO2 rutile structures with high crystallinity. For the particular synthesized morphology and design pattern, the current density and long-term stability characteristics of electron field-emission characteristics demonstrated that the flower-like RuO2 nanostructure has the potential to be used in a practical field-emission display.

Sol–gel preparation and characterization of uniform core-shell structured LaInO 3:Sm 3+/Tb 3+@SiO 2 phosphors

The core-shell structured LaInO 3:Ln 3+@SiO 2 (Ln 3+ = Sm 3+, Tb 3+) phosphors were realized by coating LaInO 3:Ln 3+ phosphors on the surface of silica microspheres via a modified Pechini sol–gel process. The phase, structure, morphology, and fluorescent properties of the materials were well characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform IR spectroscopy (FT-IR), photoluminescence (PL) spectra, cathodoluminescence (CL) spectra, and the kinetic decays, respectively. The results reveal that the obtained core-shell structured phosphors consist of amorphous silica core and crystalline LaInO 3:Ln 3+ shell, which keep the uniform spherical morphology of pure silica spheres with narrow size distribution. Upon excitation by ultraviolet (UV) irradiation or electron beam, the phosphors show the characteristic emission lines of Sm 3+ ( 4G 5/2– 6H 5/2,7/2,9/2, orange) in LaInO 3:Sm 3+@SiO 2 and characteristic emissions of Tb 3+ ( 5D 4– 7F 6,5,4,3, green) in LaInO 3:Tb 3+@SiO 2, respectively. This kind of phosphors may have potential applications in field emission displays (FEDs) based on their uniform shape, low-cost synthetic route, and diverse luminescent properties.

Field-emission properties of patterned ZnO nanowires on 2.5D MEMS substrate

We fabricated a nanowire-based field-emission display (FED) device on a 2.5D substrate using a photolithography, lift-off, thermal-evaporation, and plasma-etching process. We first fabricated a 3×3 array of microholes (diameter = 400 μm and depth = 50 μm) on a Si substrate and fabricated ZnO nanowires inside the microholes by using a thermal CVD process. The field-emission pattern image of the 3×3 array of microholes was clearly apparent. The threshold emission field was ca. 5.6 V/μm and we obtained considerable brightness when the applied voltage was 1900 V (i.e. 6.3 V/μm). Because the fabrication processes used in this study are standard semiconductor fabrication routes, the study suggests the feasibility of mass producing a nanowire-based FED device.

Light Emission Due to Energy Transfer from Gd3 + to Eu3 + Ions in Paramagnetic NaGdF4 : Eu3 + Submicrometer Disks

The paramagnetic submicrometer disks exhibit a red emission under the excitation of UV light and a low voltage electron beam. The energy transfer from the to ions in becomes less efficient with increasing doping concentration, which can be used to adjust the relative intensity of emission excited at 394 and 273 nm. The energy transfer process is less efficient at 10 K than at room temperature, which might be due to the existence of trap states that hampers the energy migration at low temperature. The cathodoluminescence (CL) spectrum and the image of are reported, and the CL mechanism is discussed. This multifunctional material with a uniform disk morphology may be potentially applied in lighting, field emission display, and magnetic resonance imaging.

Cathodoluminescence degradation of PLD thin films

The cathodoluminescence (CL) intensities of Y2SiO5:Ce3+, Gd2O2S:Tb3+ and SrAl2O4:Eu2+,Dy3+ phosphor thin films that were grown by pulsed laser deposition (PLD) were investigated for possible application in low voltage field emission displays (FEDs) and other infrastructure applications. Several process parameters (background gas, laser fluence, base pressure, substrate temperature, etc.) were changed during the deposition of the thin films. Atomic force microscopy (AFM) was used to determine the surface roughness and particle size of the different films. The layers consist of agglomerated nanoparticle structures. Samples with good light emission were selected for the electron degradation studies. Auger electron spectroscopy (AES) and CL spectroscopy were used to monitor changes in the surface chemical composition and luminous efficiency of the thin films. AES and CL spectroscopy were done with 2 keV energy electrons. Measurements were done at 1×10−6 Torr oxygen pressure. The formation of different oxide layers during electron bombardment was confirmed with X-ray photoelectron spectroscopy (XPS). New non-luminescent layers that formed during electron bombardment were responsible for the degradation in light intensity. The adventitious C was removed from the surface in all three cases as volatile gas species, which is consistent with the electron stimulated surface chemical reaction (ESSCR) model. For Y2SiO5:Ce3+ a luminescent SiO2 layer formed during the electron bombardment. Gd2O3 and SrO thin films formed on the surfaces of Gd2O2S:Tb3+ and SrAl2O4:Eu2+,Dy3+, respectively, due to ESSCRs.

The Enhanced Low-Voltage Cathodoluminescent Properties of Spherical Y2O3:Eu3+ Phosphors Coated with In2O3 and its Application to Field-Emission Displays

Dispersed and spherical Y2O3:Eu3+ red phosphor particles were prepared by the urea homogeneous precipitation method. In2O3 nanoparticles were successfully coated on the surface of the phosphor. Phase compositions, morphologies, photoluminescence (PL) spectra, and cathodoluminescence (CL) properties of Y2O3:Eu3+ phosphors before and after In2O3 coating were examined. It was found that CL properties such as luminous efficiency, lifetime, and stability of In2O3-coated phosphor screen were improved significantly, even though its PL intensity decreased compared with that of the uncoated sample. The reason is attributed to the increase of the electrical conductivity and the decrease of the charge accumulating effect. The present results prove that Y2O3:Eu3+ phosphor coated with an appropriate amount of In2O3 is more suitable to the requirement for low-voltage field-emission displays.

Surface chemical reactions during electron beam irradiation of nanocrystalline CaS:Ce3+ phosphor

The effects of accelerating voltage (0.5–5 keV) on the green cathodoluminescence (CL) of CaS:Ce3+ nanocrystalline powder phosphors is reported. An increase in the CL intensity was observed from the powders when the accelerating voltage was varied from 0.5 to 5 keV, which is a relevant property for a phosphor to be used in field emission displays (FEDs). The CL degradation induced by prolonged electron beam irradiation was analyzed using CL spectroscopy, x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The AES data showed the decrease in the S peak intensity and an increase in the O peak intensity during electron bombardment. The CL intensity was found to decrease to 30% of its original intensity after about 50 C/cm2. XPS was used to study the chemical composition of the CaS:Ce3+ nanophosphor before and after degradation. The XPS data confirms that a nonluminescent CaSO4 layer has formed on the surface during the degradation process, which may partially be responsible for the CL degradation. The electron stimulated surface chemical reaction mechanism was used to explain the effects of S desorption and the formation of the nonluminescent CaSO4 layer on the surface.

Synthesis and luminescence of sub-micron sized Ca 3Sc 2Si 3O 12:Ce green phosphors for white light-emitting diode and field-emission display applications

Ca 3Sc 2Si 3O 12:Ce 3+ phosphors with sub-micron size were successfully synthesized by a gel-combustion method. The crystal structure and morphology of the phosphors and their photoluminescence were investigated. The results indicate that the pure phase of Ca 3Sc 2Si 3O 12 can be obtained at 1100 °C of firing temperature. The particles of phosphor are basically spherical in shape with the mean size less than 1 μm. The grain of the phosphor grows up gradually with the increasing of the firing temperature. The excitation spectrum shows a broad and strong absorption band centered around 450 nm, compatible with the excited wavelength of commercial blue light-emitting diode (LED) for white LED lighting. Bright green-emission located at 505 nm is observed and the intensity of the green-emission increases with the increase of firing temperature. Additionally, under low-voltage (2.5 kV) excitation of electron beam, bright green cathodoluminescence (CL) is also observed, which is attributed to the characteristic emission from Ce 3+. Our work suggests that Ca 3Sc 2Si 3O 12:Ce 3+ phosphors are promising for both white LED and field-emission display applications.

Modifying Surface Structure to Tune Surface Properties of Vertically Aligned Carbon Nanotube Films

We report a simple etching process to modify surface of vertically aligned carbon nanotube (VACNT) arrays for their applications in superhydrophobic surface, field emission display, and sun energy conversion, etc. At a high temperature (700-800 degrees C), very low concentration water vapor in presence with Ar and hydrogen flow can be a weak oxidant, and mildly etch nanotube tips without damaging their walls. This process can be performed right after the CNT growth process. Surface of nanotube arrays becomes multi-tiered nanotube patterns with open-ended nanotubes standing straightly. Surface morphology of nanotube arrays can be tuned by changing the etching time. Water droplets on a modified nanotube surface show a large contact angle and sliding angle, which make the etched nanotube film suitable for application such as small amount liquid transport. Light absorption measurement indicated that surface roughness has no effect to improve the light absorption, indicating a different mechanism from other black material. The surface modified nanotube arrays have much increased field enhancement factor in our field emission test, showing the better field emission ability of the nanotube arrays with open tips.