Question

The conductivity of the intrinsic semiconductor at absolute temperature is

• A. Zero
• B. 0.5 eV
• C. 1.1 eV
• D. Infinity

Hint:

At absolute zero ($0\text{ K}$), all semiconductors freeze out and become perfect insulators with zero conductivity.
As temperature increases, thermal excitation generates free carriers, and conductivity begins to rise.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the electrical conductivity of a pure (intrinsic) semiconductor at absolute zero temperature ($0\text{ K}$).

Step 2: Detailed Explanation:

• In an intrinsic semiconductor (such as pure Silicon or Germanium), the valence band is completely filled with electrons, and the conduction band is completely empty at absolute zero temperature ($0\text{ K}$).

• At $0\text{ K}$, there is absolutely no thermal energy available to help valence electrons overcome the forbidden energy bandgap ($E_g \approx 1.1\text{ eV}$ for silicon) and jump into the conduction band.

• Because the conduction band contains zero free charge carriers (electrons) and the valence band has no mobile holes, there are no charge carriers available to conduct electricity.

• Consequently, the material behaves as a perfect insulator, and its electrical conductivity is exactly zero.

Step 3: Final Answer:
The conductivity of an intrinsic semiconductor at absolute zero temperature is zero.