Question

Why is a zener diode considered as a special purpose semiconductor diode draw the i-v characteristics of zener diode and explain briefly?

Answer 1

A zener diode is considered as a special purpose semiconductor diode because it is designed to operate under reverse bias in the breakdown region. We know that reverse current is due to the flow of electrons (minority carriers) from p → n and holes from n → p. As the reverse bias voltage is increased, the electric field at the junction becomes significant. When the reverse bias voltage V =Vz, then the electric field strength is high enough to pull valence electrons from the host atoms on the p-side which are accelerated to n-side. These electrons causes high current at breakdown.