Weak optical-field assisted field emission in vertically structure with nano-vacuum-gap

Vacuum electronic devices based on ballistic transport of electrons possess some outstanding advantages: no scattering, anti-irradiation and high temperature resistance. Simultaneously, electrons can release from metal surface to vacuum or gas with nanoscale gap driven by optical field emission under only a few-volt direct current bias. Moreover, low power is expected by combining its merits with light assisted field electron emission while with the help of field enhancement excited by surface plasmon. In this work, a vertically aligned structure is investigated compared to flat structure. Weak optical-field with plasmonic enhancements enhances the emitted current when DC bias significantly reduces the threshold for electron tunneling. The proposed structure may be useful for detecting, such as field strength, local field enhancement. And the designed nano-vacuum-gap is benefit for micro/nano vacuum electronic devices.