question_answer

            Reverse bias applied to a junction diode:                                                                            [AIPMT 2003]

A)  increases the majority carrier current

B)       increases the minority carrier current

C)       lowers the potential barrier          

D)       raises the potential barrier

Correct Answer: D

Solution :

In reverse biasing of a \[p-n\] junction, p-side is connected to the negative terminal of the battery and n-side is connected to positive terminal of battery. In this situation battery increases the restraining force and current through the junction is exceedingly small. The

cause of this small, current is the conduction by the minority electrons and holes obtained due to light and thermal agitation. Such circuit lowers the fermi level on n-side by an amount eV raising the barrier height to \[e({{V}_{B}}+V)\] and increasing the depletion width too.