J. E. Jung

Field emission from 4.5 in. single-walled and multiwalled carbon nanotube films

Field emission properties of 4.5 in. flat panel displays in a diode type panel using single-walled (SWNTs) and multiwalled carbon nanotube tips (MWNTs) were characterized and compared. The panel, fabricated by a slurry squeezing and surface rubbing technique, enables the generation of more emission sites by removing materials on the surface. The turn-on field of MWNTs decreased from 6.4 to 3 V/μm by treatment of the surface, and that of SWNTs also decreased, from 4.5 to 2 V/μm. The density of aligned MWNTs is approximately 2/μm2, whereas the aligned SWNTs were uniformly distributed, with densities of 5–10/μm2. As a result, SWNT films show higher emission uniformity than MWNT films. A gradual degradation over time was observed in both MWNTs and SWNTs. The current stability curve of the SWNTs decreased about 20%, while that of the MWNTs decreased less than 10%.

A simple structure and fabrication of carbon-nanotube field emission display

Abstract A triode structure of field emission displays based upon carbon-nanotube emitters is studied. In this structure, gate electrodes are located underneath cathode electrodes with an in-between insulating layer, so called an under-gate-type triode structure. The modulation of electron emission by changing gate voltages is confirmed. Charging on the insulating layer by emission electrons could be reduced by pattering the insulating layer. Results of our experiment show that emission properties are improved in the triode structure with the patterned insulator. The simple structure and fabrication process may lead the under-gate-type triode structure to the practical applications.

Triode-type field emission array using carbon nanotubes and a conducting polymer composite prepared by electrochemical polymerization

We report a method to fabricate carbon nanotubes (CNT)/conducting polymer composite films for the application of CNTs to field emission displays. The composite was prepared by a combination of electrochemical polymerization of pyrrole and electrophoretic deposition of CNTs. We obtained a uniform CNT/conducting polypyrrole polymer composite film. The CNTs were mainly coated on protrusions of the polypyrrole film and emitted electrons without rubbing and stretching. We realized a triode-type field emission array (FEA) using the CNT/polypyrrol composite. This FEA showed that the emission current was modulated by gate voltage of 30 V. The film morphology and emission characteristics of the CNT/conducting polymer composite were studied using optical microscopy, scanning electron microscopy, and an emission test in vacuum.

A 10nm platform technology for low power and high performance application featuring FINFET devices with multi workfunction gate stack on bulk and SOI

A 10nm logic platform technology is presented for low power and high performance application with the tightest contacted poly pitch (CPP) of 64nm and metallization pitch of 48nm ever reported in the FinFET technology on both bulk and SOI substrate. A 0.053um2 SRAM bit-cell is reported with a corresponding Static Noise Margin (SNM) of 140mV at 0.75V. Intensive multi-patterning technology and various self-aligned processes have been developed with 193i lithography to overcome optical patterning limit. Multi-workfunction (WF) gate stack has been enabled to provide Vt tunability without the variability degradation induced by channel dopants.

High resolution phosphor screening method for full-color field emission display applications

A polyvinyl alcohol-slurry screening technology of phosphors was studied for field emission displays with a resolution up to supervideo graphics adapter. Phosphor lines were successfully patterned as narrow as 25 μm on 6 in. glass substrates. Process conditions such as spin coating speeds, exposure time, and shadow mask layout for photolithography were related to thickness and line resolutions of phosphor. Luminance characteristics of phosphors were optimized in terms of firing processes. For ZnS:Cu, Al, ZnS:Ag, Cl, and Y2O3:Eu phosphors, the firing temperature was optimized to be 400 °C. The nitrogen ambient during the cooling process improves the stability of phosphor surface.

Development of triode-type carbon nanotube field-emitter arrays with suppression of diode emission by forming electroplated Ni wall structure

Triode-type field-emitter arrays were developed by screen printing a photosensitive paste including single-walled carbon nanotubes. Ni wall structure (NWS) was electroplated to form a thick gate to suppress diode emission induced by strong electric strengths due to an anode potential and to focus electron beams to their destined color subpixels. It was observed in computer simulations, as well in experiments that the NWS with the optimum thickness was effective in reducing the diode emission and enhancing electron-beam focusing by modifying electrical potentials around the carbon nanotube emitters. Our fully sealed field-emission display panel using the field-emitter arrays with the NWS demonstrated full color moving images without serious diode emission and with satisfactory color separation.

Synthesis and modification of red oxide phosphors for low voltage excitation

New red oxide phosphors Y2O3:Eu3+,Si4+ and (Y,Gd)2O3:Eu3+,Si4+,Bi3+ are synthesized by a coprecipitation method. Relative cathodoluminescence (CL) brightness at low voltages (⩽1 kV) is analyzed. At the low voltage excitation, luminance of the synthesized phosphors is higher than that of other commercially available red phosphors Y2O2S:Eu3+ and Y2O3:Eu3+. In particular, the difference of relative brightness between the commercially available phosphors and the synthesized Y2O3:Eu3+,Si4+ is larger at low voltages (⩽500 V) than at higher voltages. The synthesized (Y,Gd)2O3:Eu3+,Si4+,Bi3+ phosphor gives the same level of brightness as that of Y2O3:Eu3+,Si4+ at voltages greater than 500 V. (Y,Gd)2O3:Eu3+,Si4+,Bi3+ is coated with a conductive material SnO2:Eu3+. The coating of SnO2:Eu3+ shows a considerable improvement in brightness without a color shift. The excellent luminescence characteristics of (Y,Gd)2O3:Eu3+,Si4+,Bi3+ coated with SnO2:Eu3+, studied using field emitter arrays, suggests that our synthesized...

Five inch full color field emission displays with narrow gap studies

Electron beam spreading and emission current density for different shapes of microtips with bias levels are simulated for the application of high voltage or low voltage phosphors. In the simulation, the morphology of micro tips and the structural parameters of a field emission display (FED) panel are optimized in the direction of enhancing panel brightness as well as avoiding cross talk between pixels. Field emitter arrays with the optimized shape of microtips were fabricated for the application to real devices. Three different technologies for phosphor screening, electrophoresis, printing, and slurry methods, are evaluated in terms of white color coordination of screened phosphor plates in a FED panel level, leading to the selection of the best screening process for FEDs. The charging effect of phosphor surface seems to have an effect on the luminance properties of phosphors, which can be suppressed with a drive circuitry in the real FED operation. It is observed that electron beam irradiation triggers s...

Fabrication of Spindt-type tungsten microtip field emitter arrays with optimized aluminum parting layers

Spindt-type field emitter arrays of tungsten microtips have been fabricated by optimizing aluminum parting layers. The aluminum parting layers, which play a crucial role in the subsequent deposition of peeling-free tungsten films, are characterized by varying the deposition conditions. The aluminum parting layer deposited at a high vacuum level has a good stress relaxation effect, and tungsten microtip field emitter arrays, free of peeling, are successfully fabricated and show good electrical characteristics.

39.2: The Full‐Color Video Images with Uniquely‐Gated Carbon Nano‐tube Field Emission Displays

Thick-film printing processes have been applied for preparing a carbon nanotube field emission display (c-FED), which has a strong cost advantage for large-size flat panel display. For practical display applications, two types of the gated cathode structure named the normal-gate cathode and the under-gate cathode have been developed and improved. The normal-gate and the under-gate cathode structures have the driving voltages of ±35 V and ±65 V, respectively. The 5″ c-FED panel with the normal-gate cathode and the 7″ c-FED panel with the under-gate cathode were successfully implemented and excellent full-color video images were obtained.