A PN junction is the point where a p-doped semiconductor and n-doped semiconductor meet. P N junction - the junction where P and N meet. This spot, where an excess of free electrons on one side and excess of holes on the other side, creates some interesting effects that are basically the foundation of modern electronics.
The boundary between two different types of semiconductive materials.
Electronic Devices : Conventional Current Version, 9th Edition by Thomas L. Floyd