Improvement of field emission characteristics of carbon nanotube emitters using phosporous compound

Carbon nanotubes (CNTs) have attracted much attention as field emitters for x-ray tubes because of their excellent properties such as rapid operation speed, wide operation range, reduced size, light weight, and no necessity of emitter heating. This study fabricated the CNT emitters by screen-printing the CNT paste, followed by firing at 435 °C and vacuum heat treatment at 830 °C. During the high-temperature vacuum brazing, CNT emitters were often damaged by reacting with ingredients of the CNT paste. Oxidation temperature of CNTs was increased as much as ~160 °C by adding phosphorous compound. The CNT paste prepared using phosphorous compound showed a considerable improvement of field emission I-V and lifespan performances by enhancing thermal stability of CNTs.