The cause of the potential barrier in a p-n diodeis [1998]a)depletion ...
During the formation of a junction diode,
holes from p-region diffuse into n-region and
electrons from n-region diffuse into p-region.
In both cases, when an electron meets a hole,
they cancel the effect of each other and as a
result, a thin layer at the junction becomes
free from any of charge carriers. This is called
depletion layer. There is a potential gradient
in the depletion layer, negative on the p-side
and positive on the n-side. The potential
difference thus developed across the
junction is called potential barrier.
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The cause of the potential barrier in a p-n diodeis [1998]a)depletion ...
The correct option is (d) concentration of positive and negative charges near the junction.
The cause of the potential barrier in a p-n diodeis [1998]a)depletion ...
Understanding the Potential Barrier in a P-N Diode
The potential barrier in a p-n diode is a crucial concept in semiconductor physics. It arises due to the interaction between p-type and n-type materials.
Formation of the Depletion Region
- When p-type and n-type materials are joined, electrons from the n-side (which has excess negative charge carriers) diffuse into the p-side.
- Simultaneously, holes from the p-side (which has excess positive charge carriers) diffuse into the n-side.
Charge Carrier Redistribution
- This diffusion of electrons and holes leads to the recombination of charge carriers at the junction.
- As electrons leave the n-side, it becomes positively charged, while the p-side loses positive charge carriers (holes), becoming negatively charged.
Creating the Electric Field
- The region around the junction becomes depleted of mobile charge carriers, forming the depletion region.
- The opposite charges (positive on the n-side and negative on the p-side) create an electric field.
Establishment of the Potential Barrier
- This electric field opposes further diffusion of electrons and holes, establishing a potential barrier.
- The potential barrier height is influenced by the concentration of these charge carriers, which is why the correct answer is option 'D': concentration of positive and negative charges near the junction.
Conclusion
In summary, the potential barrier in a p-n diode is created through the concentration of positive charges (holes) from the p-side and negative charges (electrons) from the n-side, leading to a depletion region and an electric field that prevents further charge carrier movement.