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p–n junctions represent the simplest case of a semiconductor electronic device; a p-n junction by itself, when connected on both sides to a circuit, is a diode. More complex circuit components can be created by further combinations of p-type and n-type semiconductors; for example, the bipolar junction transistor (BJT) is a semiconductor in ...
A p–n diode is a type of semiconductor diode based upon the p–n junction. The diode conducts current in only one direction, and it is made by joining a p-type semiconducting layer to an n-type semiconducting layer. Semiconductor diodes have multiple uses including rectification of alternating current to direct current, in the detection of ...
At absolute zero temperature, all of the electrons have energy below the Fermi level; but at non-zero temperatures the energy levels are filled following a Fermi-Dirac distribution. In undoped semiconductors the Fermi level lies in the middle of a forbidden band or band gap between two allowed bands called the valence band and the conduction ...
The rectifying metal–semiconductor junction forms a Schottky barrier, making a device known as a Schottky diode, while the non-rectifying junction is called an ohmic contact. [1] (In contrast, a rectifying semiconductor–semiconductor junction, the most common semiconductor device today, is known as a p–n junction.)
The p–n junction in any direct band gap material emits light when electric current flows through it. This is electroluminescence. Electrons cross from the n-region and recombine with the holes existing in the p-region. Free electrons are in the conduction band of energy levels, while holes are in the valence energy band. Thus the energy level ...
At the junction of two different types of the same semiconductor (e.g., p-n junction) the bands vary continuously since the dopants are sparsely distributed and only perturb the system. At the junction of two different semiconductors there is a sharp shift in band energies from one material to the other; the band alignment at the junction (e.g ...
Assume that the semiconductor wafer is p-type material.Also assume a ring of n-type material is placed around a transistor, and placed beneath the transistor. If the p-type material within the n-type ring is now connected to the negative terminal of the power supply and the n-type ring is connected to the positive terminal, the 'holes' in the p-type region are pulled away from the p–n ...
Electrons in lower levels can be excited into the higher levels through thermal or photoelectric excitations, leaving a positively-charged hole in the band they left. [9] [8] Due to conservation of net charge, the concentration of electrons (n) and of protons or holes (p) in a (pure) semiconductor must always be equal. Semiconductors can be ...