Question

Explain the process of diffusion in a pn-junction.​

Answer 1

Explanation:

Diffusion is the process of movement of charge carriers due to concentration gradient along the semiconductor. In a p-n junction, n-side has excess of electrons and hence electrons diffuse from n-side to p-side. Similarly, holes diffuse from p-side to n-side

Answer 2

$\huge\underline\frak{\fbox{AnSwEr :-}}$

(1) The transfer of electrons and holes across a pn- junction is called diffusion.

(2) When a pn-junction is formed, the number of electrons on the n-side is greater than that on the p-side; also the number of holes is greater on the p-side as compared to the n-side.

(3) The large density gradient causes electrons to diffuse from the n-side to the p-side of the junction and effective holes from the p to n-side.

(4) These electrons produce negative ions by filling the holes in the p-type material.

(5) When the electrons from the n-side of a junction migrate to the p-side, they leave behind positively charged donor ions on the n-side. Effectively, holes from the p-side migrate into the n-region.

(6) This results in the formation of negatively charged acceptor ions in the p-type region near the junction and positively charged donor ionsbin the n-type region near the junction.

(7) Thus, the density of the donor and acceptor ions on the n-side and the p-side of the junction respectively decides the extent up to which the electrons and holes can diffuse across the junction