In Situ Characterization of Individual Carbon Nanotube Field Emitters with Single Crystalline Cu Tips

Field emission properties of carbon nanotubes (CNTs) filled with single crystalline Cu nanoneedles at their tips have been investigated in situ with an STM-TEM holder. The CNTs are synthesized using an alkali doped Cu catalyst by a thermal chemical vapor deposition method. Experiments show that CNTs filled with Cu have a much lower turn-on voltage (generally lower than 75V) than those without Cu (>140V). Controlled ways to remove the filled Cu-nanoneedles are developed for this comparison.