Field emission from nanomechanically modulated electron islands

Here we discuss a new approach in which the high frequency modulation is realized by ultrasonic mechanical modulation of an array of emitting pillars. The potential advantages of this concept include: (1) preserving the advantages of field emission such as room temperature operation and direct current modulation at the cathode, (2) reducing arc vulnerability by eliminating the need for a large voltage difference between the emitter tip and a nearby (gate) electrode, (3) scale-up potential to large area cathodes, (4) opportunity for significantly enhancing the emission current by phonon-assisted tunneling, and (5) opportunity for ultra-low noise operation, enabling a new class of ultra-low noise TWT amplifiers. Functioning of the devices is demonstrated for a single nanomechanical pillar. Mechanically modulated field emission is probed.