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A p–n junction diode. The circuit symbol is also shown. A p–n junction is a combination of two types of semiconductor materials, p-type and n-type, in a single crystal. The "n" (negative) side contains freely-moving electrons, while the "p" (positive) side contains freely-moving electron holes.
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 ...
Shockley derives an equation for the voltage across a p-n junction in a long article published in 1949. [2] Later he gives a corresponding equation for current as a function of voltage under additional assumptions, which is the equation we call the Shockley ideal diode equation. [3]
Inside the depletion region, both diffusion current and drift current are present. At equilibrium in a p–n junction, the forward diffusion current in the depletion region is balanced with a reverse drift current, so that the net current is zero. The diffusion constant for a doped material can be determined with the Haynes–Shockley experiment.
Carrier generation and recombination processes are fundamental to the operation of many optoelectronic semiconductor devices, such as photodiodes, light-emitting diodes and laser diodes. They are also critical to a full analysis of p-n junction devices such as bipolar junction transistors and p-n junction diodes .
The Zener diode's operation depends on the heavy doping of its p–n junction. The depletion region formed in the diode is very thin (< 1 μm) and the electric field is consequently very high (about 500 kV/m) even for a small reverse bias voltage of about 5 V, allowing electrons to tunnel from the valence band of the p-type material to the ...
As voltage increases beyond a fixed transition point, the diode begins to operate as a normal diode, where electrons travel by conduction across the P-N junction, and no longer by tunneling through the P–N junction barrier. The most important operating region for a tunnel diode is the "negative resistance" region.
The most commonly used are Schottky diodes or p-n junctions. In the measurement process the steady-state diode reverse polarization voltage is disturbed by a voltage pulse . This voltage pulse reduces the electric field in the space charge region and allows free carriers from the semiconductor bulk to penetrate this region and recharge the ...