Physics · Semiconductor and Electronic Devices

JEE Main 2026 — 5 April, Evening Shift — Question 19

In a semiconductor p-n diode, the doping concentrations on p-side and n-side are $10^{15}$ atoms/cm³ and $10^{18}$ atoms/cm³, respectively. Which one of the following statement is true?

Option A:
Widths of depletion region on either side of the interface are equal
Option B:
The depletion region width is more on p-side compared to that in n-side
Correct
Option C:
The depletion region width is more on n-side compared to that in p-side
Option D:
No depletion region forms because of unequal doping concentrations on p and n-sides

Answer: B

Step-by-step solution

For a p-n junction, $N_A x_p = N_D x_n$ .

Since $N_A < N_D$ ,

we have $x_p > x_n$ .

So depletion width is more on p-side.

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 5 April, Evening Shift
Subject: Physics
Chapter: Semiconductor and Electronic Devices
Topic: p-n Diode and its Applications