Wide band-gap semiconductors for cold cathodes: A theoretical analysis

In this paper we describe the field emission from wide band-gap semiconductor thin film electron sources as a three-step process. Internal field emission is the mechanism for electron injection at the metal-semiconductor cathode interface. Under an internal field, electrons injected into the conduction band can propagate quasi-ballistically through the thin semiconductor film. At the vacuum interface, they are field emitted across a PEA or NEA surface. Consistent with the electron injection mechanism we have done molecular dynamics simulations for GaN films with an initial energy distribution corresponding to a Fowler-Nordheim (FN) spectrum. Results demonstrate quasi-ballistic propagation and approximate preservation of the FN energy distribution. Furthermore, high levels of n-doping in GaN (similar to 10(17)cm(-3)) do not inhibit transport in thin films (<0.1 mu m).