New Metal-Air Transistor Replaces Semiconductors:
"It is widely predicted that the doubling of silicon transistors per unit area every two
years will come to an end around 2025 as the technology reaches its physical limits. But
researchers at RMIT University in Melbourne, Australia, believe a metal-based field
emission air channel transistor (ACT) they have developed could maintain transistor
doubling for another two decades.
The ACT device eliminates the need for semiconductors. Instead, it uses two in-plane
symmetric metal electrodes (source and drain) separated by an air gap of less than 35
nanometers, and a bottom metal gate to tune the field emission. The nanoscale air gap
is less than the mean-free path of electrons in air, hence electrons can travel through air
under room temperature without scattering."
See:
https://spectrum.ieee.org/nanoclast/...semiconductors