A
homojunction is a
semiconductor interface that occurs between layers of similar semiconductor material, 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 if the doping levels are different.