Feng-Yu Chuang

Field emission characteristics of carbon nanotube emitters synthesized by arc discharge

The fabrication of carbon nanotube emitters with excellent emission properties is described. The nanotubes synthesized by arc discharge are used as electron emitters. The fibrous bundles containing nanotubes were crushed, mixed with conductive pastes, and slurries and then screen printed. The scanning electron microscopy images showed that the nanotubes were disordered and the average diameter was about several tens of nanometers. In a diode structure, the electron field emission can be turned on at a field as low as 2 V/μm and attains current density as large as 7.2 mA/cm2. No significant degradation of these performance is observed for thus made electron emitters, operated under 3 V/μm (J=2.8 mA/cm2) for tens of hours. The influence of the growth condition and post-treatment process on the emission characteristics of carbon nanotubes emitters will also be discussed in this article.

22.3: A Reflective‐Type Carbon Nanotube Field Emission Display

A 3.5-inch, 60×120 pixels, reflective-type carbon nanotube emitter field-emission display has been fabricated by thick-film process. A seven-segment numerical indicator showing digit image was also demonstrated using opposed diode structure as comparison. The technical development, including design and fabrication of the nanotube emitters, phosphor, and vacuum package process was described.

Numerical indicator field emission display using carbon nanotubes as emitters

A field emission display using carbon nanotubes (CNTs) as emitters is demonstrated. The CNTs, synthesized by arc discharge, were screen printed on glass to serve as the cold cathode. The anode plate, which was indium–tin–oxide coated glass printed with P15 phosphor, was separated from the cathode using 110 μm spacers. The diode structure possesses marvelous field emission properties, including low turn-on voltage (250 V), large emission current density (2.6 mA/cm2 under 450 V) and high brightness (2500 nits). A numerical indicator with 15 pixels, driven by metal–oxide–semiconductor field effect transistors using a gate voltage of 5 V for controlling the on/off of each pixel, illustrates the capability of data addressing.

Field emission characteristics of diamondlike carbon films synthesized by pulsed laser deposition process using a Au-intermediate layer

The characteristics of the diamondlike carbon (DLC) films deposited on Au-coated silicon substrate are observed to vary markedly with the substrate temperature. Large relative proportion of sp3-bonds had pronouncedly improved the electron emission properties of the DLC films. A low turn on field as 7 V/μm and a large emission current density as 2000 μA/cm2, at 20 V/μm, were achieved for DLC/Au/Si films deposited at 200 °C. Too high a substrate temperature (i.e., 600 °C) induced graphitization that degraded the field emission behavior. The DLC/Au/Si films grow in a similar behavior as DLC/Mo/Si films, but possess substantially better field emission characteristics. The scanning electron microscopic and secondary ion mass spectroscopics analyses implied that the main factor is the improvement on the interfacial structure through the interdiffusion between DLC, Au, and Si layers.

Enhancement on field-emission characteristics of diamondlike coated Mo substrates by redox process

We have improved the emission characteristic of diamondlike carbon (DLC)-coated Mo substrates by using a reduction-oxidation (redox) process. The maximum emission current density of the DLC/Mo films increased substantially from 10 to 225 μA/cm2 with the turn-on field decreased from 12.4 to 6.4 V/μm due to redox treatment. Secondary-ion mass spectrometry spectra and x-ray diffraction patterns show that the structure of Mo films was insignificantly changed due to oxidation and reduction, whereas atomic force microscopy and transmission electron microscopy indicate that the roughness increased markedly. The electron emission characteristics of DLC films coated on redox Mo substrates are much better than those of the films coated on normal Mo film, which is ascribed to the increase in the field enhancement factor of the DC films.

Field emission display using carbon nanotubes as emitters

A fully sealed field emission display (FED), indicator, using carbon nanotubes (CNTs) as emitters is examined. The CNTs chunk, synthesized by arc discharge, were crushed, mixed with conductive pastes and then screen-printed on glass for the cold cathode. And the anode plate, an ITO glass printed P15 phosphor, was separated from cathode using 90 micrometers spacers. The indicator display performed a turn-on voltage as low as 250 V, and the emission current density 2.2 mA/cm2 under 300 V with brightness of 500 nits. The pixels, driven by open drain IC with 5 V gate voltage, showed the clock image which indicated the application of CNTs-FED. No significant degradation of this performance was observed during 1000 mins testing. The influence of printing condition and surface treatment process on the emission characteristics will also be discussed in this letter.