A micromachined vacuum triode using a carbon nanotube cold cathode

A fully integrated on-chip vacuum microtriode using carbon nanotubes as field emitters was constructed laterally on a silicon surface using micro electromechanical systems (MEMS) design and fabrication principles. Each electrode in the triode was made of a. hinged polycrystalline silicon panel that could be rotated and locked into an upright position. The device was operated at a current density as high as 16 A/cm(2). Although the transconductance was measured only at 1.3 muS, the dc output power delivered at the anode was almost 40 x more than the power lost at the grid electrode. The technique combines high-performance nanomaterials with mature solid-state fabrication technology to produce miniaturized power-amplifying vacuum devices in an on-chip form, which could potentially offer a route of integrating vacuum and solid-state electronics and open up new applications for "old-fashioned" vacuum tubes.