Editing Heterojunction (section)

{{Short description|Interface between two layers or regions of dissimilar semiconductors}}
A '''heterojunction''' is an interface between two [[Layer (electronics)|layer]]s or regions of dissimilar [[semiconductor]]s. These semiconducting materials have unequal [[band gap]]s as opposed to a [[homojunction]]. It is often advantageous to engineer the electronic energy bands in many solid-state device applications, including semiconductor lasers, [[solar cell]]s and transistors. The combination of multiple heterojunctions together in a device is called a '''heterostructure''', although the two terms are commonly used interchangeably. The requirement that each material be a semiconductor with unequal band gaps is somewhat loose, especially on small length scales, where electronic properties depend on spatial properties. A more modern definition of heterojunction is the interface between any two solid-state materials, including crystalline and amorphous structures of metallic, insulating, [[fast ion conductor]] and semiconducting materials.