Question

The drift current in a p-n junction is 20.0 µA. Estimate the number of electrons crossing a cross section per second in the depletion region.

Answer 1

Explanation:

It is given:

$\text { Drift current, } i_{d}=20 \times 10^{-6} \mathrm{A}$

Both electrons and holes are moving and these contribute to the flow of current.

It is known that the current is the charge flow’s rate.

So, it has to be found that the number of electrons crossing unit area per second.

Now, t = 1 s

id = QT

Therefore, T = 1s

So, id = ne = Q

⇒n = ide

Thus, the total amount of charge carriers traversing the depletion region is shown as n = $1013 \times 6.25$

Similarly, the number of electrons crossing the depletion region is shown as ne = n2

$\Rightarrow \mathrm{ne}=1013 \times 3.1$