Question

In an unbiased p-n junction, holes diffuse from the p-region to n-region because

(a) free electrons in the n-region attract them.
(b) they move across the junction by the potential difference.
(c) hole concentration in p-region is more as compared to n-region.
(d) All the above.

Answer 1

(a) free electrons in the n-region attract them.

Step-by-step explanation:

In a semiconductor, holes are positively charged charge carriers. A concentration gradient of holes exists in an unbiased p-n junction, moving from the p-region, where there are many holes, to the n-region. (where there are few holes). The diffusion of holes happens because free electrons in the n-region attract them due to their opposing charges. The depletion region—a region close to the junction that is deprived of mobile charge carriers—is created by this dispersion of holes over the junction. A potential difference across the junction is produced by this depletion zone, which prevents holes from dispersing further.