Equilibrium vs. Reverse Bias

In summary, under reverse bias in a PN junction, there is a small amount of current due to the movement of minority carriers. However, under equilibrium, no current flows through the junction. This is because the movement of minority carriers is cancelled out by the small amount of majority carriers that pass through, resulting in a net current of zero. In contrast, under reverse bias, not enough majority carriers pass through to cancel out the movement of minority carriers. This aspect is not commonly explained in sources, but the linked website provides a good explanation of the energy bands for equilibrium, forward and reverse bias in a PN junction.
  • #1
jalebi
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In a PN junction under reverse bias, a small bit of current exists due to the movement of minority carriers. Under equilbrium, no current passes through. Am I right in thinking that the movement of minority carriers under equilibrium is canceled by the little bit of majority carriers that passes (resulting in a net current of zero), and that under reverse bias, not enough majority carrier passes through to cancel out minority carrier movement? I couldn't find many sources that explained this aspect...
 
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  • #2
Here's a good site to explain P-N energy bands for Equilibrium, Forward and Reverse Bias:

http://hyperphysics.phy-astr.gsu.edu/hbase/solids/pnjun2.html"

Regards
 
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What is the difference between equilibrium and reverse bias?

Equilibrium refers to the state of balance or equal distribution of charges in a semiconductor device, while reverse bias occurs when the p-n junction in the device is biased in the opposite direction of its normal operation. In equilibrium, there is no net flow of current, while in reverse bias, there is a small amount of current flowing in the opposite direction of the normal operation.

How does equilibrium differ from reverse bias in terms of charge distribution?

In equilibrium, the charge distribution is uniform on both sides of the p-n junction, with the majority carriers on their respective sides. In reverse bias, the charge distribution is uneven, with majority carriers being pushed away from the junction and creating a depletion region.

What is the effect of equilibrium on the electrical properties of a semiconductor device?

In equilibrium, the electrical properties of a semiconductor device are relatively stable and predictable. The device is not actively conducting or switching, so its properties remain consistent. This is important for maintaining the device's functionality and preventing damage.

Does reverse bias have any practical applications?

Yes, reverse bias is commonly used in electronic devices to control the flow of current and create a depletion region in the p-n junction. This allows for the creation of different electrical properties and the functionality of devices such as diodes and transistors.

What are the potential risks associated with reverse bias in a semiconductor device?

Reverse bias can cause an increase in the depletion region, which can lead to a breakdown of the device if the bias is too high. This can result in permanent damage to the device and affect its functionality. It is important to carefully control the reverse bias in electronic devices to avoid these risks.

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