Question

When a p-n junction diode is forward biased, the:

• A. The barrier height and the depletion layer width both increase.
• B. The barrier height increases and the depletion layer width decreases.
• C. The barrier height and the depletion layer width both decrease.
• D. The barrier height decreases and the depletion layer width increases.

Hint:

In a forward biased diode, the barrier height decreases and the depletion region narrows, allowing current to flow more easily.

Answer 1

The Correct Option is C

To analyze forward-biased p-n junction diode behavior, we examine barrier height and depletion layer width:

A p-n junction diode combines p-type and n-type semiconductors. A built-in potential barrier forms at the junction, impeding charge carrier movement. Barrier height represents the energy threshold charge carriers must surpass to traverse the junction.

When a diode is forward biased:

• The applied external voltage lowers the barrier height, facilitating electron-hole recombination across the junction.
• The depletion layer, a region lacking charge carriers, contracts. This occurs because forward bias supplies energy that enhances electron-hole recombination, neutralizing charges in this zone.

Consequently, forward bias results in a reduction of both barrier height and depletion layer width. The conclusion is:

Both the barrier height and the depletion layer width diminish.