A survey of the tunnel-diode equivalent circuit

The DC characteristic of tunnel diodes may be explained by splitting up the total current into three fractions. Electrons pass the junction from the valence band of the n-region (Zener current) and in reverse direction (Esaki current). At a high enough forward bias, minority carrier injection will be appreciable. This current may be proportional to the summation of qV/kT provided the influence of recombination centers in the depletion layer can be neglected. Irradiation by fast neutrons will increase the number of recombination centers and will therefore increase the valley currents. It will also be noted that the tunneling process is complicated by phonon interaction and by states for electrons within the forbidden gap.