For a diode operating in forward bias, which of the following statements is
INCORRECT?

Explanation:

Incorrect Statement Analysis for a Diode Operating in Forward Bias

In a forward-biased diode, the following processes occur that affect the depletion region and the potential barrier:

Correct Option:

Option 4: The reduction in the depletion region causes a heavy flow of minority carriers across the junction.

This statement is incorrect because, in a forward-biased diode, the reduction in the depletion region primarily facilitates the flow of majority carriers (electrons in the n-region and holes in the p-region) across the junction. The minority carriers (holes in the n-region and electrons in the p-region) do not play a significant role in the current flow in a forward-biased condition. The primary current flow in a forward-biased diode is due to the majority carriers overcoming the potential barrier and recombining at the junction.

Explanation of Correct Option:

When a diode is forward-biased, the external voltage applied across the diode reduces the potential barrier at the p-n junction. This reduction in the potential barrier is due to the narrowing of the depletion region, which occurs as the majority carriers are pushed towards the junction. The applied forward voltage causes the electrons in the n-region to move towards the p-region, and the holes in the p-region to move towards the n-region. As a result, the width of the depletion region decreases, allowing more majority carriers to cross the junction and recombine, leading to an increase in the current flow through the diode.

The key points to understand here are:

• The forward bias reduces the potential barrier, making it easier for majority carriers to cross the junction.
• The depletion region narrows, allowing for the increased flow of majority carriers.
• The current in a forward-biased diode is primarily due to the flow of majority carriers, not minority carriers.

Analysis of Other Options:

Option 1: The reduction in the width of the depletion region is due to the recombination of charge carriers and immobile ions near the junction.

This statement is correct. In forward bias, as the majority carriers move towards the junction, they recombine with the oppositely charged immobile ions (donors in the n-region and acceptors in the p-region), reducing the width of the depletion region.

Option 2: The reduction in the potential barrier occurs due to the narrowing of the depletion region.

This statement is correct. The applied forward voltage reduces the potential barrier at the junction by narrowing the depletion region, allowing more majority carriers to cross the junction.

Option 3: The reduction in the depletion region allows a majority carrier flow across the junction.

This statement is correct. The narrowing of the depletion region in forward bias facilitates the flow of majority carriers (electrons and holes) across the junction, leading to an increase in current.

In summary, the incorrect statement is option 4, as it incorrectly attributes the increased current flow in a forward-biased diode to the flow of minority carriers. The correct understanding is that the majority carriers are responsible for the increased current in a forward-biased diode.