PIN diode

From Free net encyclopedia

A PIN diode (p-type, intrinsic, n-type diode) is a photodiode with a wide, undoped intrinsic semiconductor region between p-type semiconductor and n-type semiconductor regions.

A PIN diode exhibits an increase in its electrical conductivity as a function of the intensity, wavelength, and modulation rate of the incident radiation.

The benefit of a PIN diode is that the depletion region exists almost completely within the intrinsic region, which is a constant width (or almost constant) regardless of the reverse bias applied to the diode. This intrinsic region can be made large, increasing the area where electron-hole pairs can be generated. For these reasons many photodetector devices include at least one PIN diode in their construction, for example PIN photodiodes and phototransistors (in which the base-collector junction is a PIN diode).

They are not limited in speed by the capacitance between n and p region anymore, but by the time the electrons need to drift across the undoped region.

Examples

SFH203 or BPW43 are cheap general purpose PIN diodes in 5mm clear plastic case with bandwidth over 100MHz. They are used in Ronja telecommunication system. Other, more specialized PIN diodes are used in fibre optic network cards and switches.de:PIN-Diode fr:Diode PIN