Question

At absolute zero, a semiconductor is an insulator because _________.

• A. No electron is present in the conduction band
• B. All electrons occupy the valence band
• C. The value of $E_G$ is large
• D. All of the above

Answer 1

The correct option is D All of the above

At absolute zero, the band gap in a semiconductor is of order $\sim 3eV$. The electrons in the valence band do not have sufficient energy to jump to the conduction band and hence semiconductor, behaves as an insulator at 0K.