Question

In an unbiased n-p junction electrons diffuse from n-region to p-region because ______.

Options

• holes in p-region attract them.

• electrons travel across the junction due to potential difference.

• only electrons move from n to p region and not the vice-versa.

• electron concentration in n-region is more compared to that in p-region.

Answer 1

In an unbiased n-p junction electrons diffuse from n-region to p-region because electron concentration in n-region is more compared to that in p-region.

Explanation:

Diffusion is a natural process where particles move from a region of higher concentration to one of lower concentration. In an unbiased junction, the n-region has a much higher density of free electrons than the p-region, creating a concentration gradient. This gradient “pushes” electrons to migrate across the junction until an internal electric field (depletion layer) eventually stops them.