Charges can be removed from junction through recombination
Answers
Generation of eh pairs:
The generation is classified according to the energy supplied to the valence electronsto raise them to the conduction band and creating eh pairs available for coeducation into:
- Thermal generation,
-photo generation,
-impact ionization, and
-Field emission.
-The thermal generation is always present whenever the temperature of the material is greater than zero kelvin. It sets the intrinsic concentration of the mobile carriers in the material. It affects the reverse saturation currents in the junctions and sets the maximum operating temperature of devices. Thermistors as a temperature sensors are based on the thermal generation.
-The phtogeneration is the basis of the photocoductors,photodiodes , photo transisrors and photothyristor an addition to the solar cells and more applications.
-Impact ionization sets the breakdown voltage in the devices and it is utilised in the operation of the zener diode and the avalanche photo diode.
-The field emission occurs when the internal electric field is so high that it torn out valence electrons. Examples are tunnel diodes.
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