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The effect of diamondlike carbon (DLC) films coated by pulsed laser deposition technique on the electron emission characteristics of Mo tips is examined. Turn-on voltage (V0) was lowered from 40 V for Mo tips to 22 V for DLC coated Mo tips and maximum anode current (IA) was increased from ∼44 μA for Mo tips to ∼2.0 mA for DLC coated Mo tips. Maximum anode current (IA) for the DLC coated Mo tips, however, decreased during operation. Raman spectroscopy and selected area diffraction (SAD) in transmission electron microscopy (TEM) revealed that the degradation of electron emission behavior can be ascribed to the conversion of sp3-bonds, characteristic for diamond, to sp2-bonds, characteristics for graphite. The transformation of the structure is assumed to be induced by the local heat from the DLC coatings.

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.

Local electron field emission properties of diamondlike carbon (DLC) films were measured by a probe method in 1 atmosphere ambient pressure, using the modified scanning tunneling microscopic (STM) system, and the diode method. In the STM probe method, the field emission was turn on at a low bias as +2.67 V. A large emission current of 40 nA was attained at +7 volt bias voltage and the emission current density was estimated as Jt=5 A/cm2. By contrast, the current–voltage (I–V) characteristics of the same DLC films measured by diode method in 10−6 Torr ambient pressure revealed that the electron field emission was produced for a 13.2 V/μm electric field, and a high emission current density of J=160 μA/cm2 was obtained for a E=20 V/μm electric field. The geometrical enhancement factor (α), evaluated from the Fowler–Nordheim plot was around α=30, which is larger than what would be expected from a planar surface. This can be interpreted as the evidence that electrons are emitted locally from spherical SP3 clusters.

Field emission properties of plasma treated multiwalled carbon nanotube cathode layersThe 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/m and attains current density as large as 7.2 mA/cm 2 . No significant degradation of these performance is observed for thus made electron emitters, operated under 3 V/m (Jϭ2.8 mA/cm 2 ) 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.