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© 2014 IEEE. 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. In this work, the thermal annealed BNNTs exhibit a high maximum emission current density of 8.39 mA/cm2and robust long-term emission stability. The results reveal that BNNTs can be a promising emitter material for field emission devices under harsh environments.

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/cm 2 ). The field emitter with edge polishing process indicated a nearly negligible degradation of emission current in 20 h. It is considered that the high field emission performance of the field emitter is caused by the suppressed edge emission after edge polishing process. As a result, the field emitters have the higher emission current, lower field enhancement factor, and higher emission stability compared to the pristine emitter.

Boron nitride (BN) nanomaterials have excellent electrical, chemical and mechanical properties, such as high thermal conductivity, resistant to oxidation, chemical inertness, and negative electron affinity. These unique features make BN a promising cold electron emission material. In this work, we investigated on the field emission properties from BN nanotubes (BNNTs), among the various BN allotropes. BNNT is a tubular structured material like a carbon nanotube. The BN nanomaterial based field emitters were fabricated by a screen printing method. The screen printed BN emitters performed good field emission properties that presented good long-term stability and a high emission current. The detail field emission properties will be discussed.

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 source applications.

We demonstrated carbon nanotube (CNT) field emitters made by a filtration-transfer method. They showed low turn-on and threshold electric fields, which is attributed to the advantages of this method, such as the high density of emission sites, good electrical contact, strong mechanical adhesion, and low contamination of CNTs tips. In addition, the field emitters showed very stable emission stability for long operation time at the acceleration condition. Moreover, we realized flexible CNT emitters using the fabrication technique.

We fabricated the point emitter using a tip-treated carbon nanotube (CNT) fiber. The CNT point emitter showed the high emission current and good emission stability. It is considered that the excellent field emission properties are attributed to a large field enhancement factor caused by a large aspect ratio of the sharp tip of the point emitter and the tight binding of CNTs.