Question
Download Solution PDFThe forward biased diode current is:
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
Drift current:
Drift current is when electrons and holes respond to an applied electric field. Holes move in the direction of the electric field while electrons move opposite the electric field. This occurs as long as there are carriers available.
Diffusion current:
Diffusion current is when holes and electrons move from areas of high concentration, where they are the majority carrier, to areas of low concentration, where they become minority carriers. This occurs until they are uniformly distributed throughout the semiconductor.
When the diode is forward biased drift current is present, but because diffusion current grows exponentially, it dominates.
The forward-biased diode current is mostly made up of majority carrier diffusion.
Important Points
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Drift current |
Diffusion current |
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Under the action of an electric field, the charge carriers in the semiconductor material stop moving randomly and start drifting towards or away the applied electric field depends upon their nature. This drift of charge carriers produces a drift current |
In a semiconductor, there may arise a situation where the concentration of charge carriers within the crystal becomes different and hence producing a concentration gradient, due to which charge carriers cross the surface to maintain equilibrium and constitute a current which is known as diffusion current. |
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For drift current external electric field is essential. |
For diffusion, the current external field is not required. Any external energy may stimulate this process. |
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It depends on carrier concentration and external electric field. |
It depends upon the rate of charge of carrier concentration per unit length. |
Last updated on May 8, 2025
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