Field-Emission Characteristics of the Densified Carbon Nanotube Pillars Array

In this study, the densification effects of carbon nanotube (CNT) pillar array have been proved to significantly increase the field emission characteristics. Without damage to the crystallinity of CNTs, the CNT density of each densified pillar can be increased about 6.25 times as compared to the as-grown ones. Consequently, the densified CNT pillars exhibit higher electrical conductivity, better contacts, and more emission sites, which are favorable to the field emission properties. What's more, the optimum field emission characteristics occur at the condition of R/H = 2 with H = 30 mu m for both of the as-grown and densified samples because of the minimum screening effect and the proper aspect ratio. Therefore, the field emitter with densified CNT pillars of 30-mu m in height and 60-mu m in interspacing possesses the lowest turn on and threshold fields of 0.73 and 1.29 V/mu m, respectively. It implies that the densified CNT pillars are promising for the field-emission applications. (C) The Author(s) 2016. Published by ECS. All rights reserved.