Electron Field Emission From Amorphic Diamond Thin Films

The field emission of electrons from metals into vacuum due to an applied electric field is described by the Fowler-Nordheim theory. Electrons from the cathode escape into vacuum by tunneling through the barrier as opposed to jumping over h e barrier. The cunent density from the surface of the material as a function of electric field, F, and work function. 0. is given by J = lS4 F2 exd-6.83 x IO9 g3D/F) 0 where the microscopic electric field, F, is enhanced by a factor 6 over the average field E=V/d (we consider plane parallel electrodes with gap d). From the F-N theory above, it can be calculated that electron emission from metals with a typical work function of 4.5eV requires an electric field in the 1000V/pm range, which is too high for almost all applications.