According to the Wikipedia's graph of electric field in a p-n junction, there is no electric field outside the deletion region and hence no minority charge carriers move into the other side. Also, the minority charge carriers which cause the drift current are swept off. So there are no more free charge carriers in the depletion region. Then the drift current will stop whereas the diffusion current will not. So how is the equilibrium maintained in a p-n junction ? Graph

bumped to the homepage by Community 2 days ago

This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.

The free carriers leave behind charged atoms of opposite sign; they provide an electric field that balances the diffusion current. Specifically, as the electrons drift into the p-region positively charged atoms are created and similarly when holes are swept to the n-side negatively charged atoms are created. So an electric field is setup between these fixed charges that oppose the diffusion current.

There is only drift and diffusion at the edge of the depletion region. The drift and diffusion of carriers are equal and opposite so there is no net current. In the centre of the depletion region there is no drift or diffusion, and also no net current.

Your Answer


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.