Growth of carbon nanotube arrays using nanosphere lithography and their application in field emission devices

The present study investigates the patterned growth of carbon nanotubes (CNTs) by microwave plasma assisted chemical vapor deposition (MPCVD) and their field emission (FE) properties. The nanosphere monolayers were used as a mask for deposition of ultrathin (~ 3 nm) cobalt (Co) layer by DC sputtering. Periodic arrays of Co catalyst islands were obtained after the removal of spheres. Microscopic and Raman spectroscopic studies revealed the patterned growth of multiwall CNTs on catalyst islands. The CNTs length was around 10 µm and diameter was of 40–60 nm. The field emission properties were also compared with I–V characteristics of the un-patterned CNTs grown under the same conditions. The onset fields for un-patterned and patterned samples were nearly the same, 0.64 V/µm and 0.67 V/µm, respectively for a 10 µA current.