Physics - Semiconductors Question with Solution | TestHub

In an intrinsic semiconductor, charge carriers are generated by the thermal excitation of electrons from the valence band to the conduction band.

Every time an electron is excited to the conduction band, it leaves behind exactly one hole in the valence band.

Therefore, the number of free electrons per unit volume ($n_e$) is always equal to the number of holes per unit volume ($n_h$).

Thus, $n_h=n_e$.

Answer: $n_h=n_e$