Field Emission from Multiwalled Carbon Nanotubes

Films of multi‐walled carbon nanotubes are very efficient cathodes for field emission devices. Films are grown by thermal chemical vapour deposition on silicon substrates with iron as a catalyst particle. Different types of films are investigated: vertically aligned MWNT with clean and coated nanotube sidewalls. SEM, TEM and Raman spectroscopy has been used in order to determine the structure of the different films. The results show that the aligned MWNT films have excellent field emission properties with high emission current densities and low turn‐on and threshold fields. They also show that the presence of a surface coating with amorphous carbon has no impact on the efficiency of the field emission. The current density as a function of applied electric field (on multiple cycles) is reproducible up to a value of 1 mA/cm2. Exceeding this value leads to light emission from the carbon nanotube film at the investigated spot. Spectral measurements of this light shows a purely blackbody radiation effect with ...