p-n junction

Electric contact in transistors and related devices between two different types of material called p-type and n-type semiconductors.

These materials are pure semiconductor materials, such as silicon, to which impurities have been added. Materials of p-type contain "holes" (vacancies formerly occupied by electrons) that behave like positively charged particles, whereas n-type materials contain free electrons. Electric current flows more easily across a p-n junction in one direction than in the other. If the positive pole of a battery is connected to the p-side of the junction, and the negative pole to the n-side, charge flows across the junction. If the battery is connected in the opposite direction, very little charge can flow. The p-n junction forms the basis for computer chips, solar cells, and other electronic devices.

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▪ electronics

      in electronics, the interface within diodes (diode), transistors (transistor), and other semiconductor devices (semiconductor device) between two different types of materials called p-type and n-type semiconductors (semiconductor). These materials are formed by the deliberate addition of impurities to pure semiconductor materials, such as silicon. Semiconductors of p-type contain holes, mobile vacancies in the electronic structure that simulate positively charged particles, whereas n-type semiconductors contain free electrons. Electric current flows more easily across such a junction in one direction than in the other.

      If the positive pole of a battery is connected to the p-side of the junction and the negative pole to the n-side, the Fermi levels (Fermi level) of the two materials are shifted in such a way as to promote the flow of charge across the junction. If the battery is connected in the opposite direction, a reverse shift of Fermi levels is opposed by an induced electric field, and very little charge can flow. This property of the p-n junction is called rectification (rectifier) and is used in rectifiers (rectifier) to convert alternating current (AC) to direct current (DC).

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