Conductors

• Characteristics: Metals with a broad valence band close to the conduction band; the forbidden gap is narrow. Electrons require minimal energy to conduct electricity.

Semiconductors

• Characteristics: Materials like silicon, boron, and germanium that conduct electricity under specific conditions. They act as insulators at very low temperatures but conduct better at around 25°C.
• Types:
  • Pure Semiconductors (Intrinsic): Made from the same type of element (e.g., silicon, germanium). They have a narrow forbidden gap.
  • Extrinsic Semiconductors (Impure): Created by doping with other elements to form n-type or p-type semiconductors.
  • N-Type Semiconductors: Doped with group 5 elements (e.g., phosphorus), resulting in excess electrons and a negative charge.
  • P-Type Semiconductors: Doped with group 3 elements (e.g., boron), creating holes or positive gaps in the electron structure.