Question

In a junction diode the current is zero if applied forward bias voltage is 0 < V < 0.7 V. An electron experiences a force of 0.112 pN inside the depletion layer. The thickness of depletion layer is 

(1) 0.5 µm 

(2) 0.7 µm 

(3) 1 µm 

(4) 1.5 µm

Answer 1

Correct option: (3) 1 µm

Explanation:

Let E be electric field inside depletion layer due to junction potential, V, across it. x is thickness of depletion layer. Given 

F = Force experienced by electron inside depletion layer

= 0.112×10^–12 N = |e| E

The current in junction diode; in forward bias is zero is applied p.d is less than or equal to junction potential.