Characteristics of tunnel diode

Forward bias condition:
Under the forward bias condition, the immediate conduction occurs in the diode because of heavily doped conduction happen in the diode. The current in the diode reached the maximum current that diode reached a maximum value of Ip and when the voltage applied is Vp across it. The current value is decreased when more amount of voltage is applied. And it current keep decreasing unit it reaches a minimum value. This minimum value of current is called as the valley current Iv. The tunnel diode and normal PN junction diode characteristics are different from each other.
Characteristics of the tunnel diode
Reverse bias condition: 
Under the reverse bias condition, the tunnel diode act as a back diode or backward diode. In reverse bias condition, the empty state on the n side aligned with the filled state on the p side. The electron will tunnel through a potential barrier. Because of its high doping concentration tunnel diode acts as an excellent conductor.

The graph above shows that A to point of B the value of current decreases with the increases in voltage. So from figure A to B, the graph shows the negative resistance region of the tunnel diode, This region shows the most important property of the diode. Here in this region shown in, the tunnel diode produces the power instead of absorbing it.