Image Credit

Description:

This drawing shows an LED made up of P (on the left) and N (on the right) material connected to a battery with the positive terminal going to the P-type material and the negative terminal going to the N-type material. The holes are shown moving out of the P-type material and into the N-type material. The electrons are shown moving out of the N-type material and into the P-type material. As electrons fall from the conduction band to the valence band light is given off.

Source:

Wikipedia

License:

Open

Source URL:

http://en.wikipedia.org/wiki/File:PnJunction-LED-E.PNG