  The vast majority of modern microelectronic devices rely on carriers within
semiconductors due to their integrability. Therefore, the performance of these
devices is limited due to natural semiconductor properties such as band gap and
electron velocity. Replacing the semiconductor channel in conventional
microelectronic devices with a gas or vacuum channel may scale their speed,
wavelength, and power beyond what is available today. However, liberating
electrons into gas/vacuum in a practical microelectronic device is quite
challenging. It often requires heating, applying high voltages, or using lasers
with short wavelengths or high powers. Here, we show that the interaction
between an engineered resonant surface (metasurface) and a low-power infrared
(IR) laser can cause enough photoemission (via electron tunneling) to implement
feasible microelectronic devices such as transistors, switches, and modulators.
Photoemission-based devices benefit from the advantages of gas-plasma/vacuum
electronic devices while preserving the integrability of semiconductor-based
devices.
