Study of composite cathodes in electron field emission devices: Relative contributions of resonant and sequential tunneling

A simple model of a hetero-structured cathode for electron field emission was developed in order to compare resonant and sequential electron field emission currents. These two components were simultaneously computed through an iterative process. The model assumes that a certain fraction of the batch of electrons that failed to resonantly transit the structure will end up in its quasi-bound states. It was found that, while various slope changes appear in both current-field characteristics, for the sequential tunneling emission, such features are merely interference effects occurring in the potential energy barrier, prior to the electron's transition in the quasi-bound states. Thus, various space charges develop in the structure and reacts back on both the sequential and the resonant parts of the current.