Spectroscopic study for the role of polymer binding agent in the quasi-harmonic field emission behavior of polymer graphite field emission cathodes

Abstract

Graphite-based microcathodes have shown significant performance when operated as cold field emission electron sources. Specifically mentioned, cathodes that have been prepared from highly ordered pyrolytic graphite and polymer graphite pencil leads. Such cathodes are characterized by low operating voltages, a long lifetime, a cheap fabrication price, and a stable emission current. Recently, it was shown that polymer graphite cold field emission cathodes have a unique quasi-harmonic field emission behavior, where the process included emission of pulses of electrons with relatively higher emission current values. However, this behavior has not been reported for other graphite-based materials. In this paper, we study the effects of the polymer binding agent on the charge carriers' flow through the surface of polymer graphite using Raman-current spectroscopy. The results from polymer graphite were then compared to cathodes prepared from colloidal graphite conductive paint when deposited on a glass substrate. The results showed that the I(D)/I(G) ratio of polymer graphite had a fluctuating behavior, which was not the case for colloidal graphite, which had a more stable structure.