Optically stimulated picosecond field emission pulses from gated p-silicon field emitter arrays

Ultrashort current pulses of 130 ps in duration were induced in an anode circuit from a gated p-type silicon field emitter array when excited by optical pulses of 110 fs pulse width at 780 nm wavelength. The speed of the photoresponse was limited by drift transient time spread through the depletion layer below the field emitter array (FEA) and not by gate capacitance. This result identifies the geometric origin of both drift limited and diffusion limited responses and demonstrates that a properly designed optically modulated gated FEA is a promising cold photocathode for the application of next generation microwave vacuum electronic devices.