Carrier concentration-dependence of field emission from GaN

The field emission current from a n-type GaN is theoretically calculated as a function of carrier concentration n. Among the carrier-induced effects are considered internal voltage drop and band gap shirnkage. The obtained emission current density j increases slowly with increasing n. It is also found that the internal voltage drop due to field penetration is a crucial factor, while the band gap shrink-age effect is meaningful only in high carrier concentrations.