Three-dimensional Modeling of Vacuum Field Emission Nanotriodes
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