Coherent and sequential tunneling mechanisms for field electron emission through layers of wide band gap materials

A sequential two-step tunneling model was developed for the electron field emission from semiconductor cathodes covered with dielectric layers. The results are compared with a previous coherent (one-step) approach and remarkable differences are obtained. Electron heating effects are predicted in not-too-thick dielectric layers. Multiple peaks in the emitted electron energy distribution, which appear in some experiments, may be explained by the sequential field emission model.