Fabrication of low-gate-current triode field emitters with planar carbon nanoparticle cathodes

Abstract

We modified the structure of triode field emitters with planar carbon nanoparticle cathodes to reduce the gate currents. As it turned out, a simple insertion of an extra metal layer between the gate insulator and the cathode layer was sufficient for the substantial reduction of gate currents; the gate currents of the triode emitter with the modified structure never exceeded 4% of the anode currents up to anode currents of ∼250 nA, corresponding to a gate voltage of 67 V and an anode voltage 900 V. The fabrication of the modified triode structure required only four extra processing steps, compared to that of conventional triode structure, while using only conventional photolithography with a single mask. We were able to account for the gate-current reduction in terms of the modification in the electric field distribution.