Intrinsic (pure) semiconductor behavior: How well does a pure, undoped semiconductor conduct electricity at room temperature, compared with a good conductor or an insulator?

Introduction / Context:
Understanding intrinsic (pure) semiconductor behavior is the foundation for grasping how doping transforms materials into useful electronic devices. Intrinsic semiconductors such as pure silicon or germanium have far fewer free carriers than metals but far more than ideal insulators, placing them in-between and enabling controlled conductivity via doping and fields.

Given Data / Assumptions:

• Material is pure (no intentional dopants).
• Room-temperature conditions (thermal generation present).
• No strong electric field effects (e.g., breakdown) are considered.

Concept / Approach:
In an intrinsic semiconductor, thermally generated electron-hole pairs exist but at relatively low concentrations compared with electron density in metals. Hence conductivity is moderate: the material is neither a good conductor nor a true insulator. Doping with donors or acceptors increases carrier concentration dramatically, turning the material into n-type or p-type with much higher conductivity useful for diodes and transistors.

Step-by-Step Solution:

Verification / Alternative check:
Compare carrier concentrations: metals ~10^22 carriers/cm^3; intrinsic silicon ~10^10 carriers/cm^3 at 300 K. The many orders of magnitude difference explains the intermediate conductivity behavior.

Why Other Options Are Wrong:

• Conducts: Overstates conductivity; true for metals, not intrinsic semiconductors.
• Insulates: Understates; intrinsic devices do pass current measurably.
• Conducts and insulates: Contradictory.
• Superconducts at room temperature: Not applicable to intrinsic semiconductors.

Common Pitfalls:
Assuming “semiconductor” means “almost conductor” or “almost insulator”; forgetting that controlled doping is what yields practical device behavior.

Final Answer:
neither conducts nor insulates