Fabrication and field emission characteristics of high density carbon nanotubes microarrays

High density carbon nanotube field emitter arrays (CNT-FEA) in both triode and diode structures on Si were fabricated. The carbon nanotubes were synthesized using a microwave-heated CVD process. The emission image of a diode-type CNT-FEA demonstrated a brightness of ∼1800 cd/m² and a homogeneous emission quality. The cross-sectional SEM image of a triode-type emitter showed that CNTs in triode structures were shorter and less dense than CNTs in the diode-type emitters, though almost identical growth conditions of CNTs were utilized. The rough surface morphology of the emitter zone indicated the formation of chromium-silicide that could enhance the conductivity of Si substrates. Emission characteristics of the triode CNT-FEA showed that with a 1-μm SiO₂ as the spacer, very low operating voltage could be applied to the gate. Therefore, high density CNT field emitter arrays with low turn-on voltage and large emission current were successfully fabricated.