Stable field emission property of patterned MgO coated carbon nanotube arrays

Aligned carbon nanotubes (CNTs) in a specific pattern were synthesized by catalytic thermal chemical vapor deposition (CVD) technique. The carbon nanotubes were then coated with MgO layer of different thicknesses to improve the field emission property. Field emission with high stability and low turn-on voltage of about 116V was observed for the aligned nanotubes coated with a MgO layer of thickness 10nm compared to that of uncoated CNTs. The current fluctuation for 8h was found to be as low as 9% for MgO (10 nm) coated nanotubes. The field emission image indicated a very uniform emission from the whole area of the deposited CNTs on the substrate for the 10-nm-MgO-coated CNTs.