Current-Fluctuation Mechanism of Field Emitters Using Metallic Single-Walled Carbon Nanotubes with High Crystallinity

Abstract

Field emitters can be used as a cathode electrode in a cathodoluminescence device, and single-walled carbon nanotubes (SWCNTs) that are synthesized by arc discharge are expected to exhibit good field emission (FE) properties. However, a cathodoluminescence device that uses field emitters radiates rays whose intensity considerably fluctuates at a low frequency, and the radiant fluctuation is caused by FE current fluctuation. To solve this problem, is very important to obtain a stable output for field emitters in a cathodoluminescence device. The authors consider that the electron-emission fluctuation is caused by Fowler-Nordheim electron tunneling and that the electrons in the Fowler-Nordheim regime pass through an inelastic potential barrier. We attempted to develop a theoretical model to analyze the power spectrum of the FE current fluctuation using metallic SWCNTs as field emitters, owing to their electrical conductivity by determining their FE properties. Field emitters that use metallic SWCNTs with high crystallinity were successfully developed to achieve a fluctuating FE current from field emitters at a low frequency by employing inelastic electron tunneling. This paper is the first report of the successful development of an inelastic-electron-tunneling model with a Wentzel-Kramers-Brillouin approximation for metallic SWCNTs based on the evaluation of FE properties.

Field Emission from Carbon Nanostructures

“…Current-fluctuation mechanisms of field emitters using metallic single-walled carbon nanotubes with high crystallinity have also been recently discussed [107]. This study is related to the possibility of using field emitters as a cathode electrode in a cathodoluminescence device.…”

Field Emission Cathodes to Form an Electron Beam Prepared from Carbon Nanotube Suspensions

“…Finally, homogenous dispersion of the high crystalline metallic CNTs with minimal damage for field-emission purposes is not a trivial task. This point ensures the CNT cathode film stability during emission [30].…”

“…The measured sample is placed in the UHV chamber and heated to~200 • C, in order to attain the required pressure and to ensure the presence of residual gases (coming from the cathode materials, e.g., not completely removed non-water solvent), and water is excluded or at least highly reduced. In such a condition, stable emission is expected, though it is not always the rule [29][30][31]. To visualize the electron emission, as an anode, the phosphor film is used deposited on a semi-transparent or transparent substrate.…”

Field-emission durability employing highly crystalline single-walled carbon nanotubes in a low vacuum with activated gas

“…The density of the electric potential concentrated at the tips of CNTs is decreased to a certain extent depending on their length and diameter, and the distance between neighboring CNTs. Electrons tunnel to the outside through the area with a thin quantum energy barrier localized near the tips of CNTs [33][34][35][36][37]. Table 1 summarizes the FE properties of each sample determined from the J-E curves in the cases of high vacuum and low vacuum with argon in figure 4(a).…”