High-Performance Field Electron Emitters Fabricated Using a Free-Standing Carbon Nanotube Film

Abstract

The carbon nanotube (CNT) field emitter was fabricated using a thin free-standing CNT film, indicating a lineshape CNT field emitter. Field emission properties of the CNT field emitter were investigated in both diode and triode configurations. The CNT field emitter showed a low turn-on electric field of 1.8 V/µm and a high emission current of 40.3 mA, corresponding to the emission current density of 96 A/cm 2 in the diode configuration. It also exhibited a high anode current of 40 mA, corresponding to the anode current density of 95.2 A/cm 2 in the triode configuration. In addition, the CNT field emitter showed a good electron beam transmittance of 86.4% and excellent emission stability without degradation for 15 h. The main reason for the high performance of our CNT field emitter is caused by the high density of emission sites at the edge of the CNT film.

Enhanced Field Emission Properties of CNT Film Emitters through Densification using Nitric Acid

“…After centrifugation at 20,000 g for 40 min, short and well-dispersed CNTs were collected by a pipet from the CNT solution. The collected CNT solution was poured into a vacuum filtration system with an anodic aluminum oxide (AAO) membrane to form a CNT film on the AAO membrane. ,, Both distilled (DI) water and isopropyl alcohol (IPA) were used to remove SDS within the CNT film. The CNT film was separated from the membrane using a 1 M sodium hydroxide (NaOH) solution, then soaked in IPA for 20 h, and finally dried in ambient air.…”

“…However, the aforementioned CNT field electron emitters generally have difficulties in simultaneously achieving two characteristics. Recently, we have suggested a new type of CNT emitter, which is fabricated using a free-standing CNT film to realize both high emission current and high emission current density. , As the CNT film is entirely composed of CNT networks held together by the van der Waals force without any additional organic, inorganic, or metal materials, it is very important to enhance the van der Waals force between CNTs to obtain stable CNT field electron emitters. Densification of CNT films is considered a useful way to enhance van der Waals forces between CNT networks.…”

Densification effect on field emission characteristics of CNT film emitters for electron emission devices

“…Figure 1 shows a process diagram presenting the fabrication and densification processes of the CNT film, and a crosssectional schematic diagram of field electron emission measurement of the CNT film emitter. The fabrication process of the CNT film is as follows [23]. The t-MWCNTs synthesized by catalytic chemical vapor deposition method [24] were thermally annealed (950 °C, 30 min, 10 −5 Torr) to remove amorphous carbon and other impurities.…”