Question

When the conductivity of a semiconductor is due only to the breaking up of the covalent bonds, the semiconductor is known as:

• A. Donor
• B. Extrinsic
• C. Intrinsic
• D. Acceptor

Hint:

Intrinsic semiconductors are pure materials where electrical conductivity arises due to thermal excitation of electrons.

Answer 1

The Correct Option is C

Step 1: Nature of intrinsic semiconductor
An intrinsic semiconductor is a pure semiconductor material (such as silicon or germanium) that contains no significant amount of impurity atoms.

Step 2: Origin of charge carriers
In an intrinsic semiconductor, conductivity arises due to thermal energy. This energy breaks some covalent bonds, generating equal numbers of electrons and holes (electron–hole pairs).

Step 3: Conduction mechanism
Both electrons in the conduction band and holes in the valence band contribute to electrical conduction.

Final Conclusion:
Thus, when conductivity is due to the breaking of covalent bonds producing electron–hole pairs, the semiconductor is called an intrinsic semiconductor.