[[File:PN band.gif|thumb|400px|right|A homojunction PN junction. The band at the interface is continuous. In forward bias mode, the depletion width decreases. Both p and n junctions are doped at a 1e15/cm3 doping level, leading to built-in potential of ~0.59 V. Observe the different Quasi Fermi levels for conduction band and valence band in n and p regions (red curves).]]
A '''homojunction''' is a semiconductor interface that occurs between layers of similar semiconductor material;<ref>Yang 1978, p. 141.</ref> these materials have equal band gaps but typically have different doping. In most practical cases a homojunction occurs at the interface between an n-type (donor doped) and p-type (acceptor doped) semiconductor such as silicon, this is called a p–n junction.
This is not a necessary condition as the only requirement is that the same semiconductor (same band gap) is found on both sides of the junction, in contrast to a heterojunction. An n-type to n-type junction, for example, would be considered a homojunction even if the doping levels are different.
The different doping level will cause band bending, and a depletion region will be formed at the interface, as shown in the figure to the right.
== See also == * Transistor * p–n junction * Band bending * Doping (semiconductor) == Notes == {{reflist}}
== References == * Yang, Edward S (1978). ''Fundamentals of semiconductor devices''. McGraw-Hill. ISBN 0070722366
== External links == * {{Commonscatinline|PN-junction band diagrams}}
Category:Semiconductor structures