Carrier concentration-dependence of field emission from semiconductors

The carrier concentration-dependence of field emission is theoretically investigated calculating the conduction band contributions to emission current for several n-type semiconductors. The calculated field emission current densities j are found to increase slowly with increasing concentration n for n-type Ge, Si, GaN semiconductors. For n-type GaAs, j increases before a certain value of n and decreases after it. Such n-dependence of all semiconductors varies slightly with the applied field. It is to note that the internal voltage drop due to field penetration is a crucial quantity in determining the n-dependence. The band gap shrinkage effect is meaningful only in high carrier concentrations. q1999 Elsevier Science B.V. All rights reserved