Electrical Conduction in Solids

Types of Electrical Conduction in Solids

• Metallic Conduction: Occurs in metals, where free electrons (also known as delocalized electrons) move freely, carrying electrical charge.
• Semiconductor Conduction: Occurs in semiconductors, where electrons are not entirely free, but can be excited to conduct electricity with the help of thermal or light energy.
• Ionic Conduction: Occurs in ionic solids, where ions move to conduct electricity.

Mechanisms of Electrical Conduction in Solids

• Band Theory: Explains conduction in solids based on the energy levels of electrons in a material. Valence band and conduction band are separated by an energy gap.
• Free Electron Model: Simplifies the behavior of electrons in metals, treating them as a gas of free electrons.

Factors Affecting Electrical Conduction in Solids

• Temperature: Increases in temperature can:
  • Increase conduction in metals (as electrons gain kinetic energy)
  • Increase conduction in semiconductors (as more electrons are excited to the conduction band)
  • Decrease conduction in ionic solids (as ionic motion is hindered)
• Doping: Introducing impurities into semiconductors can:
  • Increase conduction (p-type or n-type doping)
  • Create regions with different electrical properties (p-n junctions)

Applications of Electrical Conduction in Solids

• Electronics: Diodes, transistors, and integrated circuits rely on semiconductor conduction.
• Electrical Power Distribution: Metallic conduction enables efficient transmission and distribution of electrical power.
• Energy Storage: Ionic conduction is crucial in batteries, where ions move between electrodes.