Question: Q. 9. The graph of potential barrier versus width of depletion region for an unbiased diode is shown in $A$. In comparison to $A$, graphs $B$ and $C$ are obtained after biasing the diode in different ways. Identify the type of biasing in $B & C$ and justify your answer.
U] [CBSE SQP 2016]
B
C
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Solution:
Ans. Diode $B$ is reverse biased.
When diode is reverse based, the barrier height increases as the direction of applied voltage (V) and the direction of barrier potential (V) is same. The effective barrier height under reverse biased is $\left(V_{0}+V\right)$.
Diode $\mathrm{C}$ is forward biased.
$1 \frac{1}{2}$
As the direction of applied voltage is opposite to the barrier potential, therefore, the effective barrier height is reduced to $\left(\mathrm{V}_{0}-\mathrm{V}\right)$.
[CBSE Marking Scheme 2016]
