The dependence of the current on emitter size is obtained for a high-curren
t planar diode with a discrete emitting surface. It is shown that if the di
stance between the emitters appreciably exceeds their size, the dependence
of the current on the ratio of the emitter size to the diode gap is a power
dependence with an exponent of 3/2. The voltage dependence of the current
obeys the "three-halves" law up to higher voltages than that for a planar d
iode with a homogeneous emitting surface. (C) 1999 American Institute of Ph
ysics. [S1063-7842(99)01806-1].