Calculation of bulk states contributions to field emission from GaN

The field emission current from an n-type GaN is theoretically calculated as a function of carrier concentration n. The obtained emission current density j increases slowly with increasing n even though the band bending has the opposite n dependence. In evaluating the n dependence of field emission, the internal voltage drop due to field penetration is found to be crucial. The current density j is also calculated for several electron affinities chi. It seems that at the lowest chi and at high field, F, the calculated emission currents from the bulk states can be close to the measured values. The electric field at the GaN conical tip is found to be very high in the large area and yield such a large emission current as measured in experiment. (C) 1998 American Vacuum Society. [S0734-211X(98)07902-5].