what is pn junction
A pân junction. The circuit symbol is shown: the triangle corresponds to the p side. See also: pân diode and Diode Â§ Semiconductor diodes. A pân junction is a boundary or interface between two types of semiconductor material, p-type and n-type, inside a single crystal of semiconductor.he electrons that cross the pân junction into the p-type material (or holes that cross into the n-type material) will diffuse in the near-neutral region. Therefore, the amount of minority diffusion in the near-neutral zones determines the amount of current that may flow through the diode.