Electron over-barrier emission mechanism of single layer graphene

We propose a model which describes the sideband electrons emission from a vertically aligned monolayer graphene with an internal time-oscillating barrier and static surface barrier. Our results show that electron emission is governed by the over-barrier emission process, where the emitting current line density J [nA/nm] is only dependent on the amplitude V₁ and frequency ω of the oscillating barrier, which is characterized by 0<; γ= V₁/ hω<;1. It is found that J is maximized around the optical frequency at ω= 10¹⁴ to 10¹⁵ rad/s, and J is higher for larger γ.