Question

At absolute zero temperature, an intrinsic semiconductor behaves as

• A. conductor
• B. superconductor
• C. insulator
• D. semiconductor

Hint:

At absolute zero, intrinsic semiconductors act as insulators because thermal energy is required to generate charge carriers by exciting electrons across the band gap.

Answer 1

The Correct Option is C

Let’s break this down step by step to determine the behavior of an intrinsic semiconductor at absolute zero and why option (3) is the correct answer.
Step 1: Understand the behavior of an intrinsic semiconductor
An intrinsic semiconductor is a pure semiconductor without impurities. Its conductivity depends on the excitation of electrons from the valence band to the conduction band, which requires thermal energy to overcome the band gap.
Step 2: Analyze the behavior at absolute zero
At absolute zero temperature ($T = 0 \, \text{K}$), there is no thermal energy available to excite electrons across the band gap. As a result:

• No electrons are in the conduction band.
• The valence band is completely filled.
• No charge carriers (electrons or holes) are available for conduction.

Therefore, the intrinsic semiconductor behaves as an insulator, as it cannot conduct electricity.
Step 3: Confirm the correct answer
Since an intrinsic semiconductor has no free charge carriers at absolute zero, it behaves as an insulator, matching option (3).
Thus, the correct answer is (3) insulator.