Enhanced electron emission from carbon nanotubes through density control using <i>in situ</i> plasma treatment of catalyst metal

Abstract

We controlled the density of carbon nanotubes (CNTs) through in situ NH3 plasma pretreatment and investigated field emission properties with the density variation. Ni catalytic layer was transformed into small nanoparticles with NH3 plasma pretreatment time and power. As NH3 plasma pretreatment time was increased, the growth rate of grown CNTs was gradually decreased. Also, the density of CNTs reduced from 2×109 to 8×106/cm2 with an increase in NH3 plasma pretreatment time from 10 to 30 min for the Ni layer of 10 Å. With a decrease in the density of CNTs, the emission current density was increased and turn on electric field was decreased. We obtained large and uniform emission current (about 9 mA/emission area of 0.49 cm2) from CNTs film with the density of 8×106/cm2.