Question

Intrinsic Si lattice does not contain any free electrons at 0 K as all the electrons in Si lattice have contributed to form bonds. Therefore, at 0 K Si acts as an insulator. Explain how Si becomes a semiconductor at room temperature

Answer 1

Answer:

As the temperature increase electrons move from valence to conduction  band.

Explanation:

There exist a very small band gap between semiconductor, so even at room temperature (a very small increase in Temperature) electrons move from valence to conduction band.