Question

Name the two important processes that occur during the formation of a p-n junction

Answer 1

At the junction there is diffusion of charge carriers due to thermal agitation; so that some of electrons of n-region diffuse to p-region while some of holes of p-region diffuse into n-region. Some charge carriers combine with opposite charges to neutralise each other. Thus near the junction there is an excess of positively charged ions in n-region and an excess of negatively charged ions in p-region. This sets up a potential difference called potential barrier and hence an internal electric field Ei across the junctions. Thank you