A p–n junction is formed at the boundary between a p-type and n-type semiconductor created in a single crystal of semiconductor by doping, for example by ion implantation, diffusion of dopants, or by epitaxy (growing a layer of crystal doped with one type of dopant on top of a layer of crystal doped with another type of dopant). If two separate pieces of material were used, this would introduce a grain boundary between the semiconductors that severely inhibits its utility by scattering the electrons and holes.
p–n junctions are elementary "building blocks" of most semiconductor electronic devices such as diodes, transistors, solar cells, LEDs, and integrated circuits; they are the active sites where the electronic action of the device takes place. For example, a common type of transistor, the bipolar junction transistor, consists of two p–n junctions in series, in the form n–p–n or p–n–p.
The discovery of the p–n junction is usually attributed to American physicist Russell Ohl of Bell Laboratories.
Other articles related to "junctions":
... and the semiconductor material also creates metal–semiconductor junctions called Schottky diodes ... reduce the width of those depletion layers to such an extent that the metal-semiconductor junctions do not act as diodes ... These non-rectifying junctions behave as ohmic contacts regardless of applied voltage polarity ...
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