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We reported fabrication and field emission properties of carbon nanotube (CNT) field emitters which indicated the point-type CNT film emitter and line-type CNT film emitter. The CNT film field emitters were made by cutting CNT film using a razor. The CNT film emitters showed good emission properties such as the low turn-on field, the high emission current in a triode configuration. Especially, the...
We fabricated the point-type CNT emitter for cold cathode x-ray source applications. The CNT point emitter was made by CNT film with a triangular tip shape, which was clamped using two stainless steel plates. Electrical properties of the point-type CNT emitter measured in triode structure showed the low turn-on and threshold electric fields, the high emission current and relatively high electron transmittance...
Field emission properties of boron nitride (BN) nanomaterials have been studied for years to apply it at harsh ambient condition. However, the field emitters fabricated using the BN nanomaterials have limitations to utilize it as field emission devices due to their poor emission performances. Here, we report much enhanced field emission properties of the BN nanomaterial with low turn-on electric field,...
We demonstrated high field emission performance of carbon nanotube paste emitters, which were fabricated by using graphite filler, instead of commonly used metal or SiO2, or SiC particle fillers. The emitter with an emission area of 0.7 mm in diameter shows a highest current of 8.4 mA before electrical arcing events, corresponding to a current density of 2.2 A/cm2. The emitter shows a stable current...
We report novel two-dimensional (2D) shaped carbon nanotube (CNT) field emitters using triangular-shaped CNT films and their field emission properties. Using the 2D shaped CNT field emitters, we achieved remarkable field emission performance with a high emission current of 22mA (equivalent to an emission current density >105A/cm2) and long-term emission stability at 1mA for 20h. We also discuss...
A sheet electron beam source is demonstrated using a line-shape carbon nanotube (CNT) field emitter. The line-shape CNT field emitter shows large emission current under the small applied voltage. Moreover, the emitted electron is well-confined without any focusing lens.
Point-type carbon nanotube (CNT) field emitters have attracted much interest because they can promise a focused electron beam spot with a high emission current. The point-type CNT field emitters can be used for diverse applications such as x-ray tubes, electron beam sources and microwave sources. Here, we report fabrication and emission performance of various point-type field emitters made by CNTs.
We demonstrated high performance field emission of carbon nanotube (CNT) field emitters fabricated on a graphite rod. After the thermal annealing at 900 °C in vacuum ambient, the emitter showed a high emission current of 11.3 mA, corresponding to an emission current density of 5.8 A/cm2. The CNT emitter indicated a low turn-on field of 1.9 V/µm and stable emission stability at a current of 1 mA. In...
Boron nitride nanotubes (BNNTs) have been studied as a field emission material due to their unique and excellent properties such as high oxidation resistance and negative electron affinity. However, field emission properties of BNNT field emitters were rarely reported until now because it is difficult to synthesize high purity BNNTs and fabricate stable BNNT field emitters. Here, we report high field...
We demonstrate a very efficient synthesis of vertically-aligned ultra-long carbon nanofibers (CNFs) with sharp tip ends using thermal chemical vapor deposition. Millimeter-scale CNFs with a diameter of less than 50nm are readily grown on palladium thin film deposited Al2O3 substrate, which activate the conical stacking of graphitic platelets. The field emission performance of the as-grown CNFs is...
We demonstrated a novel point-typed carbon nanotube field emitters using a triangular-shaped carbon nanotube films. We also investigated the field emission properties of the field emitters according to the tip angles. The wider field emitters exhibited higher emission current, and the field emitters with a tip angle of 120° showed extremely high emission current density over 104 A/cm2 (> 10 mA)...
Boron nitride (BN) nanomaterials have negative electron affinity, which makes BN a promising cold electron emission material. BN nanotube (BNNT) field emitters show excellent oxidation endurance after high temperature thermal annealing at 600 °C in air ambient. There is no damage to the BNNTs after the thermal annealing at a temperature of 600 °C and also no degradation of field emission properties...
We demonstrated the fabrication of point-typed field emitters by using carbon nanotube films on graphite rods and investigated their field emission properties. The field emitter showed an increased emission current and an improved long-term emission stability after edge polishing process. The highest emission current of the field emitter was increased from 2.0 mA to 4.3 mA (1.1 A/cm2). The field emitter...
We demonstrated field emission properties of a CNT point emitter fabricated by using CNTs on a graphite rod. The emitter has the highest current of 6.3 mA; the corresponding current density is 1.6 A/cm2. The emitter is stable at a current of 0.1 mA for 20 hours. It also showed a small and uniform emission pattern at the phosphor coated ITO glass. Our point emitter could be a good candidate for X-ray...
We demonstrated carbon nanotube point emitters fabricated by using free standing carbon nanotube films. The point emitters showed stable and large emission current under the small applied voltage. Moreover, the emitted electrons were focused well without any focusing lens
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