  Vacuum nanodevices are devices that the electron transport through them is
based on electron field emission from a nano-eimtter to another opposite
electrode through a vacuum channel. Geometrically asymmetric metal-vacuum-metal
structures were demonstrated to have energy conversion ability for elec-
tromagnetic waves in the optical range. Combining the ability of these
structures to convert optical signals into recti ed current and the ability of
vacuum nanotriodes to control the eld emission current can allow direct
processing on converted optical signals using a single device. In this paper, a
three-dimensional quantum-mechanical method, rather than the approximate
Fowler-Nordheim theory, is used for modeling the eld emission process in
vertical-type vacuum nanotriodes consisting of an emitter, a collector and a
gate. The electron transport through the device is computed using a
transfer-matrix technique. The potentials of vacuum nanotriodes in the current
recti cation and modulation are investigated at low volt- ages. The e ects of
varying the structure geometrical parameters on the recti ed current are also
studied. The obtained results show that a great enhancement in the recti cation
properties is achievable when the gate and the collector are connected through
a DC source. It is also demonstrated that a small variation in the gate voltage
can be used either to modulate the recti ed current or to switch the device
into a resonant tunneling diode.26
