PN junction in forward bias

By Saumitra Raj Mehrotra1, Gerhard Klimeck1

1. Purdue University

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Animations

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Abstract

A PN junction is formed by joining p-type and n-type doped semiconductors together in very close contact. The p- and n-type semiconductors are conducting because of the available free carriers. However, because the carriers diffuse into the adjoining p and n regions by a process called recombination the contact region is non-conducting. This region is called depletion region.

PN junction

The application of a positive bias on the p-type end will lead a PN junction into the forward biased mode of operation. Positive biases lower the bands in p region. As a result, electrons in an n region and holes in a p region will have smaller barriers to overcome and diffuse to the other side. This leads to a shrinking depletion region and increased conductivity.

Credits

Image rendered using nanoHUB tool PN Junction Lab (http://nanohub.org/resources/229)

Permitting reuse under the Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA)

Cite this work

Researchers should cite this work as follows:

  • Saumitra Raj Mehrotra; Gerhard Klimeck (2010), "PN junction in forward bias," http://nanohub.org/resources/8797.

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