The field emission of a carbon nanotube (CNT) pillar array has been improved significantly by plasma treatment in a mixture of hydrogen and nitrogen gases. The plasma treatment for 30 s on a pillar array decreased the turn- on electric field from 0.48 to 0.37 V/mu m and increased the field enhancement factor from 6200 to 6900. The emission current density increased by a factor of approximate to 40. We report in this letter the technique of generating nanotips on CNT pillars with an enormous potential to become a tool for the control and manipulation of CNTs and nanostructures. (C) 2008 American Institute of Physics.