Valence Band FillingHardQuestion 20213
Question
At 0 K, a pure semiconductor:
- ABehaves like a metal
- BBehaves like a perfect insulator — all valence band states filled, conduction band emptyCorrect
- CHas maximum conductivity
- DHas equal electron and hole densities at non-zero value
Correct answer
Behaves like a perfect insulator — all valence band states filled, conduction band empty
Explanation
At 0 K, no thermal energy → no electrons excited across the gap → fully filled valence band, completely empty conduction band → exactly zero conductivity (perfect insulator behaviour). Above 0 K, thermal excitation creates electron-hole pairs.