Ultra-low turn-on field and ultra-high field emission current density from pillar array design of carbon nanotubes with optimum R/H ratio

It is reported that field emission can effectively enhanced for aligned carbon nanotubes (CNTs) as field emitters when the ratio of distance between neighboring nano-tubes to the height of each individual CNT is about 2. In this paper, we proposed pillar array design of CNTs to fulfill the optimum R/H ratio (the ratio between inter-pillar distance R and pillar height H) with high density of aligned CNTs by changing H while maintaining R at 100μm, respectively. From the obtained experimental results, ultra-low turn-on field at 0.81V/μm and the ultra-high field emission current density (1A/cm
²
at 2.8 V/μm) were achieved at the optimum R/H ratio of 2 with the inter-pillar distance of 100μm.