Robust micro-gated carbon nanotube field emitter arrays

An integrated gate (micro-gate) is necessary to enable field emission from carbon nanotubes (cNTs) at low voltages. We have demonstrated emission from cNTs grown inside two such types of micro-gated structures, one a gated silicon post, another having an open aperture. In the first configuration anode currents up to 1 mA (from 0.5 mm² area) were obtained at gate voltages as low as 40 V. In the second configuration the gate current was 2.5% of the anode current. The current was more stable than typical of most field emitter arrays, and the arrays did not fail by arcing at high currents. The emission current was increased by ambient water vapor and hydrogen, but was unaffected by xenon. Energy spectra of the emitted electrons show that the emission current saturated at energies just below the Fermi level, showing the electron transport to the emission site is requires a significant voltage.