Effect of ion beam etching on the field emission of carbon nanotube arrays

Vertically aligned carbon nanotube (CNT) arrays were synthesized on a silicon substrate via vaporization of ethylene (C2H4) using a hot-filament chemical vapor deposition (HF-CVD) method. The as-grown arrays were etched using a dual ion mill and the field emission properties of the CNTs before and after etching were studied. It was found that the structure of the emitter tips and the morphology of the CNT arrays influenced the field amplification factor (β) which is an important parameter for the field emission properties. SEM and TEM analyses indicated that the changes in the macroscopic morphology of the CNT array and structure of the CNT tips were responsible for the improvement in emission after 10 min etching.