Triode-type field emission device having field emitter composed of emitter tips with diameter of nanometers and method for fabricating the same

A method for fabricating a triode-type field emission device, comprising the steps of:

• (a) forming a cathode on an insulating substrate;
• (b) patterning a metal layer on the cathode;
• (c) selectively growing a field emitter on the metal layer, wherein the field emitter includes a plurality of emitter tips and each emitter tip has the diameter of nanometers;
• (d) forming an insulating layer on the field emitter;
• (e) forming a conductive layer of a gate electrode on the insulating layer;
• (f) selectively removing the conductive layer of the gate electrode and generating a gate hole;
• and
• (g) exposing the field emitter by etching the insulating layer,
• wherein the distance between the gate electrode and the field emitter is a quarter of the diameter of the gate hole.