Nanoscale Field-Emission Devices for High-Frequency Operation

Fowler-Nordheim field emission—the emission of electrons under a strong local electric field—has been studied for over a century. However, the usage of devices based on this mechanism has been limited to niche applications like high-power RF systems and field emission displays. The preference for solid-state devices relies on its low cost, long lifetimes, low operation voltage, and simplicity of fabrication and scalability. Yet, with the advent of modern nanofabrication procedures it has been possible to fabricate nanoscale field emission devices that offer several advantages over traditional semiconductor devices. For instance, vacuum allows ballistic transport with no lattice scattering, which could allow a higher cut-off frequency than the MOSFET.

In this work, we propose the fabrication of in-plane gold vacuum field emission two-terminal device. The geometry consists of a coplanar waveguide that feeds into a multi-tip array separated by vacuum gaps of 30-50 nm between both terminals, which permits under 15 V operation. The planar multi-tip geometry is designed to minimize capacitance, overall leading to a high cut-off frequency for fast operation.