用特殊工艺把P型和N型半导体结合在一起后,在它们交界面上所形成的特殊带电薄层,称做PN结,如图1所示。由图可知,PN结在P型材料(称为P区)一侧带负电,在N型材料(称为N区)一侧带正电,形成一个内电场。该电场的方向由N区指向P区。 After the P-type and N-type semiconductors are combined by a special process, a specially charged thin layer formed at the interface between them is called a PN junction, as shown in FIG. 1. It can be seen from the figure that the PN junction is negatively charged on the side of the P type material (referred to as the P region) and is positively charged on the side of the N type material (referred to as the N region) to form an internal electric field. The direction of the electric field is directed from the N region to the P region.