Question

Assertion (A): We cannot form a p-n junction diode by taking a slab of a p-type semiconductor and physically joining it to another slab of an n-type semiconductor.
Reason (R): In a p-type semiconductor \( \eta_e \gg \eta_h \) while in an n-type semiconductor \( \eta_h \gg \eta_e \).

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false and Reason (R) is also false.

Hint:

In semiconductors, p-n junctions are formed by joining p-type and n-type materials, regardless of the hole and electron concentration ratios.

Answer 1

The Correct Option is C

To determine the correct answer, let's analyze both the assertion and the reason provided. 

Assertion (A): "We cannot form a p-n junction diode by taking a slab of a p-type semiconductor and physically joining it to another slab of an n-type semiconductor."

This assertion is true. When a p-type and an n-type semiconductor are physically joined without a continuous lattice structure, it does not result in a functional p-n junction diode. This is because there will be a high concentration of defects and inconsistencies at the interface, preventing proper charge carrier movement and the establishment of a depletion region necessary for diode function.

Reason (R): "In a p-type semiconductor \( \eta_e \gg \eta_h \) while in an n-type semiconductor \( \eta_h \gg \eta_e \)."

This reason is false. In a p-type semiconductor, the concentration of holes (\( \eta_h \)) is much greater than the concentration of electrons (\( \eta_e \)), i.e., \( \eta_h \gg \eta_e \). Conversely, in an n-type semiconductor, the concentration of electrons (\( \eta_e \)) is much greater than the concentration of holes (\( \eta_h \)), i.e., \( \eta_e \gg \eta_h \).

Given that the assertion is true while the reason provided is incorrectly stated, we conclude:

Correct Answer: Assertion (A) is true, but Reason (R) is false.